CoStar Group (CSGP) 10-K risk factor changes: FY2025 vs FY2024

| • | | | If we are unable to attract and retain new clients, particularly subscribers to our information, analytics, and online marketplace services, our [removed: revenues] [added: revenue] and financial position will be adversely affected. | | |

| • | | | Failure to develop and introduce new or upgraded information, analytics, and online marketplace services or to shift focus from current services with less demand could decrease our [removed: revenues] [added: revenue] and our profitability. | | |

| • | | | If we are unable to hire qualified [removed: persons] [added: people] for, or retain and continue to develop our sales force, or if our sales force is unproductive, our [removed: revenues] [added: revenue] could be adversely affected. | | |

| • | | | If [removed: internet search engines do not prominently feature] our websites [removed: on the] [added: are not prominently featured in internet] search engine [removed: results page,] [added: results, if internet search engines integrate technologies or adopt ranking methodologies that decrease] traffic to our [removed: websites would decrease, and,] [added: websites, or] if we are unable to maintain or increase traffic to our marketplaces, our business and operating results could be adversely affected. | | |

| • | | | Our strategic [removed: transactions, including the acquisition of Matterport,] [added: transactions] may be subject to regulatory approvals and may not be completed as contemplated. | | |

[removed: | • | | | We] [added: *We] may be unable to [removed: complete the acquisition of Matterport or otherwise] realize the benefits of the [removed: pending] [added: acquisition of either] Matterport [removed: acquisition,] [added: or Domain,] which could have an adverse effect on [removed: us. | | |][added: us.* On February 28, 2025, the Company completed the Matterport Acquisition, and on August 27, 2025, the Company]

| • | | | Technical problems or disruptions could damage our reputation and lead to reduced demand for our information, analytics, and online marketplace services, lower [removed: revenues] [added: revenue] and increased costs. | | |

| • | | | Attention to [removed: ESG] [added: corporate responsibility] matters may require us to incur additional costs or otherwise adversely impact our business. | | |

| • | | | [removed: Our services could be less attractive and our revenues] [added: We] may [removed: decrease if we fail to obtain or retain listings from third parties,] [added: not be able] to maintain or establish relationships with third-party listing providers, maintain stable data feeds, or to comply with the rules and compliance requirements of MLSs. | | |

*We may not be able to attract and retain new clients, which could adversely affect our [removed: revenues] [added: revenue] and financial position.

Our success and [removed: revenues] [added: revenue] depend on attracting and retaining subscribers to our information, analytics, and online marketplace services, which generate the largest portion of our [removed: revenues.*] [added: revenue.*] Our renewal rate, net new booking and [removed: revenues] [added: revenue] may not grow, or could decrease, if we cannot attract new customers, continue to keep our cancellation rate low, and continue to sell new services to our existing customers, which may occur as a result of several factors, including, continuing global economic and geopolitical volatility, economic pressures, and the impact of inflation on our costs and on customer spending; the business failure of current clients; customer decisions that they do not need our services or to use alternative services; customers’ and potential customers’ budgetary constraints; consolidation in the real estate and/or financial services industries; data quality; technical problems; competitive pressures; or devaluation of the local currencies of international customers relative to the U.S. dollar which impairs the purchasing power of such customers.

*We may not be able to successfully develop and introduce new or upgraded online marketplace services, information, and analytics that are attractive to our users and advertisers or successfully combine or shift focus from current services with less demand, which could decrease our [removed: revenues] [added: revenue] and our profitability.* Our future business and financial success will depend on our ability to continue to anticipate the needs of customers and potential customers and to successfully introduce new and upgraded services, including services that make our marketplaces useful for users and attractive to advertisers.

To be successful, we must be able to quickly adapt to changes in the industry, as well as rapid technological changes, including AI [removed: and machine learning,] [added: Technologies,] by continually enhancing our information, analytics, and online marketplace services.

As a result, we must continually invest resources in research and development, both through internal investments and the acquisition of intellectual property from companies that we have acquired, to improve the appeal and comprehensiveness of our [removed: services] [added: services,] and effectively incorporate new technologies, which could have an adverse effect on our financial results.

If these development efforts and marketing campaigns do not increase brand awareness, site traffic, subscriptions for marketplaces [removed: services] [added: services,] and/or [removed: revenues,] [added: revenue,] the cost of these campaigns could have an adverse effect on our results of operation.

If we eliminate or phase out a service and are not able to offer and successfully market and sell an alternative service, our [removed: revenues] [added: revenue] may decrease, which could have an adverse effect on our results of operations.

The markets for information systems and services and for online marketplaces in general are highly competitive and rapidly [removed: changing.*] [added: changing in response to changing consumer behavior and new technological advancements.*] If we are unable to compete successfully against our existing or future competitors, our business, results of operations, or financial condition could be adversely affected.

[removed: Competitors] [added: Competitors, or future competitors,] may introduce different solutions that attract users away from our [removed: services] [added: services, such as AI-powered platforms that provide access to real estate agents, real estate data, and related content without directing users to our marketplaces,] or provide solutions similar to ours that have the advantage of better branding or marketing resources.

Our competitors may be able to undertake more effective marketing campaigns, obtain more data, adopt more aggressive pricing policies, make more attractive offers to potential employees, subscribers, advertisers, distribution partners, and content providers, or may be able to respond more quickly to new or emerging [removed: technologies or changes] [added: technologies, including the integration of generative AI Technologies] in [added: response to changing consumer behavior or] user requirements.

Increased competition [added: or failure to adapt effectively to technological shifts] could result in lower [removed: revenues] [added: revenue] and higher expenses, which would reduce our profitability.

*Our operating results and [removed: revenues] [added: revenue] are subject to fluctuations, and our quarterly financial results may be subject to market cyclicality, each of which could negatively affect our stock price.* The real estate market may be influenced by general economic conditions, economic cycles, changes in interest rates, seasonality, and many other factors, which in turn may impact our financial results.

If we are unable to adequately respond to economic, seasonal, or cyclical conditions, our [removed: revenues,] [added: revenue,] expenses, and operating results may fluctuate from quarter to quarter.

Our operating results, [removed: revenues,] [added: revenue,] and expenses may fluctuate for many reasons, including those described in this paragraph and below:

Fluctuations in our financial results, [removed: revenues,] [added: revenue,] and expenses may cause the market price of our common stock to decline.

The real estate market may be adversely impacted by many different factors, including lower than expected job growth or job losses resulting in reduced real estate demand; reduced real estate demand due to continued remote work policies or a period of or rising elevated interest rates, elevated inflation, slowing transaction volumes, and other macroeconomic trends that negatively impact investment returns; excessive [removed: speculative] [added: speculation in] new construction in localized markets resulting in increased vacancy rates and diminished rent growth; unanticipated disasters or global health events; and other adverse events such as decreased growth in the working age population resulting in reduced demand for all types of real estate.

A downturn in the real estate market, including as a result of increased interest rates or a decline in leasing activity and absorption rates may affect our ability to generate [removed: revenues] [added: revenue] and may lead to more cancellations by our current or future customers, either of which could cause our [removed: revenues] [added: revenue] or our revenue growth rate to decline and reduce our profitability.

Consolidation, or other cost-cutting measures by our customers, may lead to cancellations of our online marketplace services, information, and analytics by our customers, reduce the number of our existing clients, reduce the size of our target market, or increase our clients’ bargaining power, all of which could cause our [removed: revenues] [added: revenue] to decline and reduce our profitability.

If cancellations, reductions of services, and failures to pay increase, and we are unable to offset the resulting decrease in [removed: revenues] [added: revenue] by increasing sales to new or existing customers, our [removed: revenues] [added: revenue] may decline or grow at lower rates.

*If we are unable to hire qualified persons for, or retain and continue to develop our sales force, or if our sales force is unproductive, our [removed: revenues] [added: revenue] could be adversely affected.* In order to support [removed: revenues] [added: revenue] and revenue growth, we need to continue to develop, train, and retain our sales force.

If we are unable to hire qualified sales personnel and develop and retain our sales force, including sales force management, or if our sales force is unproductive, our [removed: revenues] [added: revenue] or growth rate could decline and our expenses could increase.

[removed: *Our business depends on retaining and attracting highly capable management and operating personnel.*] Our success depends in large part on our ability to retain and attract management and operating personnel, including our [removed: President] [added: Founder] and Chief Executive Officer, Andrew Florance, and our other officers, and key employees.

If we are unable to successfully execute our investment strategy, we may experience decreases in our [removed: revenues,] [added: revenue,] or revenue growth rate, and operating margins.

If we are unable to do so successfully, our brands may be adversely affected, and we may not be able to maintain or grow our current revenue and profit levels.* To remain competitive and stimulate consumer and business demand, we must successfully manage new product introductions and transitions of [added: products and services.]

*We may be unable to increase awareness of our brands, including CoStar, LoopNet, [added: Matterport, BizBuySell, STR,] Apartments.com, Homes.com, Land.com, [removed: BizBuySell, STR, Ten-X, and] OnTheMarket, [added: and Domain] which could adversely affect our business.* We rely heavily on our brands, which we believe are key assets of our company.

Awareness and differentiation of our brands are important for attracting and expanding the number of users of, and subscribers to, our online marketplaces, such as the LoopNet Network, the Apartments.com Network, the [removed: Homes.com and] [added: Homes.com,] OnTheMarket residential marketplaces, [removed: and] the Land.com [removed: Network.][added: Network, and Domain.]

*If [removed: internet search engines do not prominently feature] our websites [removed: on the] [added: are not prominently featured in internet] search engine [removed: results page,] [added: results, if internet search engines integrate technologies or adopt ranking methodologies that decrease] traffic to our [removed: websites would decrease, and, if] [added: websites, or] we are unable to maintain or [removed: increase] [added: grow] traffic to our marketplaces, our business and operating results could be adversely affected*. Our ability to generate [removed: revenues] [added: revenue] from our marketplace business depends, in part, on our ability to attract users to our websites.

Google, Bing, DuckDuckGo and other internet search engines drive traffic to our websites, including CoStar.com, the LoopNet Network, the Apartments.com Network, our Homes.com and OnTheMarket residential marketplaces, the Land.com Network, [removed: Ten-X.com,] and [removed: BizBuySell.][added: BizBuySell Network.]

For example, when a user enters [removed: in] a search query for an apartment building name or address into an internet search engine, the internet search engine’s ranking of our Apartments.com or Homes.com webpages will determine how prominently such webpages are displayed on the search engine results page.

Increases in our operating expenses could negatively impact our operating results if we are unable to generate more [removed: revenues] [added: revenue] through increased sales of subscriptions to our marketplace products.

*If real estate professionals or other advertisers reduce or cancel their advertising spending with us and we are unable to attract new advertisers, our operating results would be harmed.* Our marketplace businesses, including the LoopNet Network, the Apartments.com Network, the [removed: Homes.com and] [added: Homes.com,] OnTheMarket [added: and Domain] residential marketplaces, and the Land.com Network, depend on advertising [removed: revenues] [added: revenue] generated primarily through sales to persons in the real estate industry, including broker, agents, [added: property managers and owners, real estate agents, and other advertisers.]

| • | | | We may be unable to realize the benefits of the Matterport Acquisition or the Domain Acquisition. | | |

| • | | | If third-party suppliers upon which Matterport relies are not able to fulfill its needs, Matterport's ability to timely and cost effectively bring its hardware products to market could be affected. | | |

| • | | | Our services could be less attractive and our revenue may decrease if we fail to obtain or retain listings from third parties. | | |

| • | | | Failure to comply with the terms of the underlying open source software licenses could restrict our ability to deliver our products or services or subject us to litigation or other actions. | | |

| • | | | We are expanding our operations outside of the United States, which may subject us to increased business, regulatory, and economic risks that could harm our business. | | |

Moreover, rapid advancement of generative AI Technologies may reduce the barrier to entry for new competitors.

Additionally, tariffs, trade barriers and restrictions, and other acts by governments to protect domestic markets or to retaliate against the trade tariffs and restrictions of other nations could negatively affect our business operations.

*Our business depends on retaining and attracting highly capable management and operating personnel*.

Additionally, we are in varying stages of development in relation to our products and internal business processes involving AI Technologies, and there can be no assurance that our investments in such technologies will achieve the expected benefits.

With respect to our products or services that incorporate AI Technologies, the market for such products and services is rapidly evolving and unproven in many industries, including our own, and important assumptions about the characteristics of targeted markets, pricing, sales cycles, cost, performance, and perceived value associated with our services or products may be inaccurate.

Our failure to successfully develop and commercialize our products or services involving AI Technologies could harm our ability to expand our business; provide, improve and diversify our product offerings; continue our operations and efficiently manage our operating expenses; and respond effectively to competitive developments, which could adversely affect our business, results of operations, and financial condition.

In addition, if internet search engines expand their services into digital real estate marketplaces, they could leverage their scale, user base, and technology to compete with our websites.

Such competition could reduce traffic to our websites, limit our marketplaces' visibility to customers, and diminish the value of our advertising and subscription products.

If current

completed the Domain Acquisition.

*If third-party suppliers upon which Matterport relies are not able to fulfill its needs, Matterport’s ability to timely and cost effectively bring its hardware products to market could be affected.* Matterport relies on a limited number of suppliers to supply its hardware components for its cameras and other hardware products, including in some cases only a single supplier for some products and components.

This reliance on a limited number of manufacturers increases its risks, since Matterport does not currently have proven reliable alternative or replacement manufacturers beyond these key parties.

In the event of interruption, we may not be able to increase capacity from other sources or develop alternate or secondary sources, and if such sources become available, they may result in material additional costs and substantial delays.

Unexpected changes in business conditions, materials pricing, labor issues, wars, trade policies, natural disasters, health epidemics, trade and shipping disruptions, port congestions, and other factors beyond our or our suppliers’ control could also affect these suppliers’ ability to deliver components to us or to remain solvent and operational.

Such disruptions could adversely affect our business if we are not able to meet customer demands.

In addition, some of our suppliers are located in China.

Our access to suppliers in China may be limited or impaired as a result of tariffs, including those that have been recently introduced by the current U.S. administration, or other government restrictions in response to geopolitical factors.

There is no guarantee we may be able to continually use alternative suppliers and alternative parts as we scale production to meet our growth targets.

Additionally, if our suppliers do not accurately forecast and effectively allocate production or if they are not willing to allocate sufficient production to us, it may reduce our access to components and require us to search for new suppliers.

The unavailability of any component or supplier could result in production delays, idle manufacturing facilities, product design changes, and loss of access to important technology and tools for producing and supporting our products, as well as impact our capacity expansion and our ability to fulfill our obligations under customer contracts.

Moreover, new product launches or product design changes by us have required, and may in the future require, us to procure additional components in a short amount of time.

Our suppliers may not be willing or able to sustainably meet our timelines or our cost, quality, and volume needs, or to do so may cost us more, which may require us to replace them with other sources.

If we face supply constraints for any of the reasons described above, it may not be possible to obtain or increase supplies on acceptable terms, which may undermine our ability to satisfy customer demands in a timely manner.

For example, it may take a significant amount of time to identify a manufacturer that has the capability and resources to build and supply necessary hardware components in sufficient volume.

Identifying suitable suppliers can be an extensive process that requires us to become satisfied with our suppliers’ quality control, technical capabilities, responsiveness and service, financial stability, regulatory compliance, and labor and other ethical practices.

Accordingly, a loss of any significant suppliers or manufacturers would have an adverse effect on our business, financial condition, and operating results.

Because we make extensive use of third-party service providers, such as cloud and SaaS services, significant cyberattacks that disrupt or result in unauthorized access to third-party IT Systems could materially impact our operations and financial results.

our service providers.

regarding the environmental and/or social impacts, risks, and opportunities of our business.

If we are no longer able to obtain certain data from third parties or from brokers, our brands and our business, results of operations, and financial condition could be materially impacted.

could require us to expend significant financial or other resources.

Additionally, the scope of intellectual property protection in the field of AI and machine learning is currently under development, and there is uncertainty and ongoing litigation in different jurisdictions as to the degree and extent of protection warranted for AI and machine learning systems and their relevant system outputs.

For example, the law is uncertain across jurisdictions regarding the copyright ownership of content that is produced in whole or in part by generative AI tools.

If we fail to obtain protection for the intellectual property rights concerning our AI Technologies or their outputs that we seek to claim as proprietary, or later have our intellectual property rights invalidated or otherwise diminished, which could adversely affect our business, reputation and financial condition.

These risks may be exacerbated from impacts, or perceived impacts, of emerging technologies (including, but not limited to, AI Technologies integrated into our products and services).

| | | | | | |

products and services.

property managers and owners, real estate agents, and other advertisers.

*We may be unable to complete the acquisition of Matterport or otherwise realize the benefits of the pending Matterport acquisition, which could have an adverse effect on us.* On April 22, 2024, we announced that we had entered into the Matterport Merger Agreement to acquire Matterport.

Pursuant to the Matterport Merger Agreement, and subject to the terms and conditions contained therein, at the closing of the acquisition, we will acquire all of the outstanding shares of Matterport Common Stock in a cash and stock transaction.

The closing of the acquisition is subject to customary conditions, including: expiration or termination of the applicable waiting periods under applicable antitrust laws; no injunction, award, law or order restraining, enjoining or otherwise prohibiting or making illegal the consummation of the Mergers; accuracy of each party’s representations and warranties, subject in most cases to materiality or material adverse effect qualifications; compliance by each party with its obligations under the Matterport Merger Agreement in all material respects; and with respect to the other party, there not having occurred since the date of the Merger Agreement any event, development, change or occurrence that has had or would reasonably be expected to have had, individually or in the aggregate, a material adverse effect.

On July 3, 2024, Matterport and CoStar Group each received a request for additional information and documentary materials (the “Second Request”) from the FTC in connection with the FTC’s review of the transaction.

The effect of the Second Request is to extend the waiting period imposed by the HSR Act until 30 days after Matterport and CoStar Group have each substantially complied with their respective Second Requests, unless that period is extended or terminated sooner by the FTC.

Matterport and CoStar Group certified they were in substantial compliance with the Second Request in November 2024 and January 2025, respectively.

Each of Matterport and CoStar Group continue to work cooperatively with the FTC in its review of the Transaction and expect that the Transaction will be completed in the first quarter of 2025, subject to the expiration or termination of the waiting period under the HSR Act and the satisfaction or waiver of the other closing conditions specified in the Matterport Merger Agreement.

Until the completion of the acquisition, we will operate independently of Matterport.

In addition, the amount of stock consideration offered per share of Matterport Common Stock is based on an exchange ratio that will be fixed prior to closing, subject to a collar, based on our share price, and will not be adjusted to account for changes in Matterport’s business, assets, liabilities, prospects, outlook, financial condition, or results of operations, or any other changes during the pendency of the acquisition, including any change in the market price of, analyst estimates of or projections relating to Matterport Common Stock, which could adversely affect our business, results of operations, and financial condition.

If we are unable to

An increasing number of organizations, including large merchants, businesses, technology companies, and financial institutions, as well as government institutions, have disclosed security incidents, disruptions to, and breaches of their or third-party providers’ IT Systems, some of which have involved sophisticated and highly targeted attacks, including on websites, mobile applications, and infrastructure, following a trend of cyberattacks increasing in frequency and magnitude on a global basis.

Our IT Systems, or those of third parties on which we rely, may be disrupted or damaged and our Confidential Information may be compromised, corrupted, lost, or stolen.

results of operations, particularly if we elect not to raise our rates for our services to offset the increase.

These risks may be exacerbated from impacts, or perceived impacts, of emerging technologies (including, but not limited to, machine learning) on human rights, privacy, or other social considerations, which may result in reputational harm, compliance costs for any new rules or interpretations, or other adverse impacts on our operations and financial performance.

This could markedly decrease the

If our cash flows and capital resources are insufficient to fund our debt service obligations,

internal and/or external customer-facing operations.

For example, the GDPR creates data protection requirements in the EU and UK and imposes substantial fines for breaches of the data protection rules.

The GDPR increased our responsibility and liability in relation to personal data that we process.

The interpretation and application of many privacy and data protection laws are uncertain.

These laws may be interpreted and applied in a manner that is inconsistent with our existing data management practices or the features of our products.

If so, in addition to the possibility of negative publicity, fines, lawsuits, and other claims and penalties, we could be required to fundamentally change our business activities and practices or modify our products, which could harm our business.

Potential factors that could cause actual results to differ materially from those discussed in any forward-looking statements include, but are not limited to, those stated [removed: above in] under the heading “Cautionary Statement Concerning Forward-Looking Statements” and in Item 1A.

Our principal [removed: online marketplace services, information, and analytics] [added: services] are described in the following [removed: paragraphs by type of service:][added: paragraphs:]

CoStar is our subscription-based integrated platform for commercial real estate intelligence, which includes information about commercial real estate properties, properties for sale, comparable sales, tenants, space available for lease, industry professionals and their business relationships, industry [removed: news] [added: news,] and market [removed: status and provides benchmarking for the hospitality industry, lease analytical capabilities, and risk management capabilities for lenders.][added: status.]

We expect [removed: CoStar's] [added: Commercial Real Estate's] revenue growth rate for the year ending December 31, [removed: 2025] [added: 2026] to [removed: decelerate] [added: moderate] compared to the revenue growth rate for the year ended December 31, [removed: 2024 primarily] [added: 2025,] due to [removed: a] [added: the] lack of benefit from [removed: converting legacy STR customers to our new CoStar-based benchmarking product] [added: the Matterport Acquisition] realized in [removed: 2024.][added: 2025.]

Our LoopNet Network of commercial real estate websites [removed: offer subscription-based,] [added: offers] online marketplace services that enable commercial property owners, landlords, and real estate agents working on their behalf to advertise properties for sale or for lease.

Homes.com offers real estate agents subscription memberships promoting the agent's [removed: home] listings and profile on our [removed: websites.][added: websites, as well as the ability for real estate agents and homeowners to promote a single listing.]

[removed: Homebuyers] [added: Our residential marketplaces enable renters] and [removed: real estate agents use Homes.com] [added: homebuyers] to find [added: their] dream homes [removed: using] [added: by combining] our proprietary research and neighborhood content [removed: combined] with listing [removed: information.][added: information, while enabling property owners, managers, and real estate agents to advertise their properties.]

OnTheMarket [removed: is a property portal in the U.K., which primarily] hosts agents' listings on a subscription basis.

[removed: Our other marketplaces include Ten-X, an] [added: Other Commercial Real Estate includes revenue from the Matterport Acquisition, BizBuySell Network, and Ten-X's] online [removed: auction platform] [added: auctions] for commercial real [removed: estate, our Land.com Network, and our BizBuySell Network.][added: estate.]

[removed: The Land.com Network provides online marketplaces for rural lands for sale and] [added: Our] BizBuySell Network provides online marketplaces for businesses and franchises for sale.

[removed: Subscription-based Services][added: *Subscription-based Services*]

We recognize subscription [removed: revenues] [added: revenue] on a straight-line basis over the life of the contract.

For the years ended December 31, [added: 2025,] 2024, [removed: 2023,] and [removed: 2022,] [added: 2023,] our annualized net new bookings of subscription-based services on all contracts were approximately [removed: $250] [added: $308] million, [removed: $286] [added: $250] million, and [removed: $305] [added: $286] million, respectively.

Net new bookings is calculated based on the annualized amount of change in [removed: the Company's] [added: our] sales bookings resulting from new subscription-based contracts, changes to existing subscription-based contracts, and cancellations of subscription-based contracts for the period reported.

However, information regarding net new bookings is not comparable to, nor should it be substituted for, an analysis of our [removed: revenues] [added: revenue] over time.

[removed: Revenues] [added: Revenue] from our subscription-based contracts were approximately [added: 93%,] 96%, [removed: 95%,] and [removed: 93%] [added: 95%] of total [removed: revenues] [added: revenue] for the years ended December 31, [added: 2025,] 2024, [removed: 2023,] and [removed: 2022,] [added: 2023,] respectively.

For the trailing 12 months ended December 31, [added: 2025,] 2024, [removed: 2023,] and [removed: 2022,] [added: 2023,] our contract renewal rates for [added: existing company-wide CoStar Group] subscription-based services for contracts with a term of at least one year were approximately 89%, [removed: 90%,] [added: 89%,] and 90%, respectively; and, therefore, our cancellation rates for those services [removed: for] [added: during] the same periods were approximately 11%, [removed: 10%,] [added: 11%,] and 10%, respectively.

Our trailing 12-month contract renewal rate may decline as a result of negative economic conditions, consolidations among our [removed: clients,] [added: customers,] reductions in customer spending, or decreases in our customer base.

[removed: Revenues] [added: Revenue] from our subscription-based contracts with a term of at least one year were approximately [added: 76%,] 81%, [removed: 82%,] and [removed: 80%] [added: 82%] of total [removed: revenues] [added: revenue] for the trailing 12 months ended December 31, [added: 2025,] 2024, [removed: 2023,] and [removed: 2022,] [added: 2023,] respectively.

The decrease in the percentage of our revenue from subscription-based contracts with a term of at least one year from [removed: 2023 to] 2024 [added: to 2025] was primarily due to [removed: increases in sales of shorter-term Multifamily products.][added: Domain, which sells listings on its platforms on a transactional basis, as well as the transactional products and services sold by Matterport.]

We are committed to supporting, improving, and enhancing our [added: information, analytics, and] online marketplace solutions, [removed: information, and analytics,] including expanding and improving our offerings for our client base and site users, including property owners, property managers, buyers, commercial tenants, and residential renters and buyers.

Our key priorities for [removed: 2025] [added: 2026] currently include:

We [removed: plan to launch] [added: launched] our LoopNet [removed: brand] [added: branded advertising products] in [removed: France and] Spain and [added: France and] continue to expand our footprint of commercial [removed: listings.][added: listings in these markets.]

We also [removed: plan to begin the integration of] [added: offer SaaS for lease management under] the CoStar Real Estate Manager and Visual Lease [removed: products.][added: brands.]

[added: We intend to continue to assess the need for additional investments in] our business in order to develop and distribute new services and functionality within our current platform or expand the reach of, or otherwise improve, our current service offerings.

Any new investments, changes to our service offerings, or other unforeseen events could cause us to experience reduced [removed: revenues] [added: revenue] or generate losses and negative cash flow from operations in the future.

The non-GAAP financial measures that we may disclose include EBITDA, [removed: adjusted] [added: Adjusted] EBITDA, [removed: and adjusted] [added: Adjusted] EBITDA [removed: margin.][added: margin, Adjusted Net Income, and Adjusted EPS.]

EBITDA is our net income [added: (loss)] before interest income or expense, net, other expense or income, net, loss on debt extinguishment, income taxes, depreciation and amortization.

Adjusted EBITDA is different from EBITDA because we further adjust EBITDA for stock-based compensation expense, acquisition- and integration-related costs, restructuring [added: and related] costs, [added: including certain advisory fees,] and settlements and impairments incurred outside our ordinary course of business.

Adjusted EBITDA margin represents [removed: adjusted] [added: Adjusted] EBITDA divided by [removed: revenues] [added: revenue] for the period.

We [removed: may] disclose [removed: adjusted] [added: Adjusted EBITDA, Adjusted] EBITDA [added: margin,] and [removed: adjusted EBITDA margin] [added: Adjusted Net Income] on a consolidated basis in our earnings releases, investor conference calls, and filings with the SEC.

We view EBITDA, [removed: adjusted] [added: Adjusted] EBITDA, [removed: and adjusted] [added: Adjusted] EBITDA [removed: margin] [added: margin, Adjusted Net Income, and Adjusted EPS] as operating performance measures.

We believe that the most directly comparable GAAP financial measure to [removed: EBITDA] [added: EBITDA, Adjusted EBITDA,] and [removed: adjusted EBITDA] [added: Adjusted Net Income] is net income.

We believe the most directly comparable GAAP financial measure to [removed: adjusted] [added: Adjusted EPS and Adjusted] EBITDA margin [removed: is] [added: are earnings per diluted share and] net income [added: (loss)] divided by [removed: revenue.][added: revenue, respectively.]

In calculating EBITDA, [removed: adjusted] [added: Adjusted] EBITDA, [removed: and adjusted] [added: Adjusted] EBITDA [removed: margin] [added: margin, Adjusted Net Income, and Adjusted EPS,] we exclude from net income [added: (loss)] the financial items that we believe should be separately identified to provide additional analysis of the financial components of the day-to-day operation of our business.

EBITDA, [removed: adjusted] [added: Adjusted] EBITDA, [removed: and adjusted] [added: Adjusted] EBITDA [removed: margin] [added: margin, Adjusted Net Income, and Adjusted EPS] are not measurements of financial performance under GAAP and should not be considered as a measure of liquidity, as an alternative to net [removed: income,] [added: income (loss),] or as an indicator of any other measure of performance derived in accordance with GAAP.

Investors and potential investors in our securities should not rely on EBITDA, [removed: adjusted] [added: Adjusted] EBITDA, [removed: and adjusted] [added: Adjusted] EBITDA [removed: margin] [added: margin, Adjusted Net Income, and Adjusted EPS] as a substitute for any GAAP financial [removed: measure.][added: measure, including net income (loss) and earnings per diluted share.]

In addition, we urge investors and potential investors in our securities to carefully review the GAAP financial information included as part of our Annual Reports on Form 10-K and Quarterly Reports on Form 10-Q that are filed with the SEC, as well as our quarterly earnings releases, and compare the GAAP financial information with our EBITDA, [removed: adjusted] [added: Adjusted] EBITDA, [removed: and adjusted] [added: Adjusted] EBITDA [removed: margin.][added: margin, Adjusted Net Income, and Adjusted EPS.]

EBITDA, [removed: adjusted] [added: Adjusted] EBITDA, [removed: and adjusted] [added: Adjusted] EBITDA [removed: margin] [added: margin, Adjusted Net Income, and Adjusted EPS] may be used by management to internally measure our operating and management performance and may be used by investors as supplemental financial measures to evaluate the performance of our business.

We have spent more than [removed: 30] [added: 35] years building our database of commercial real estate information and expanding our markets and services partially through acquisitions of complementary businesses.

CoStar Group is a leading provider of online real estate marketplaces, information, analytics, and 3D digital twin technology in the property markets, based on the numbers of unique visitors and site visits per month; provides more information, analytics, and marketing services than many of our competitors; offers the most comprehensive commercial real estate database available; and has the largest commercial real estate research department in the industry.

We have created and compiled a standardized platform of real estate information and analytics and online marketplaces where industry professionals, consumers of commercial and residential real estate, including apartments, and the related business communities, can continuously interact and facilitate transactions by efficiently accessing and exchanging accurate and standardized real estate-related information.

Our service offerings span all property types, including office, retail, industrial, multifamily, residential, land, mixed-use, and hospitality.

We operate, develop products, and deliver our services in two reportable segments, Commercial Real Estate and Residential Real Estate.

Our Commercial Real Estate segment offers commercial real estate information and analytics, online marketplaces, and 3D digital twin technology and its principal brands are CoStar, including CoStar Real Estate Manager and CoStar with STR benchmarking, LoopNet, Matterport, BizBuySell, and Ten-X.

Our Residential Real Estate segment hosts marketplaces which aggregate consumer demand for homes that they can rent or buy and we sell marketing and leads to the agents, owners, landlords, and property management companies that need to reach those consumers with their offerings.

Our flagship brands in the U.S. are Apartments.com, Homes.com, and Land.com.

Domain and OnTheMarket are our leading marketplaces in Australia and the U.K., respectively.

During the fourth quarter of 2025, we changed the composition of our segments from geography-based to product portfolio-based.

This change aligns with the internal reporting used by the CODM to allocate resources and assess the performance of the business.

See Notes 2, 3 and 13 of the Notes to the Consolidated Financial Statements included in Part IV of this Report for additional information on the segments change.

Our services are primarily derived from a database of building-specific information and offer customers specialized tools for accessing, analyzing, and using our information.

Over time, we have enhanced and expanded, and we expect to continue to enhance and expand, our existing information, analytics, and online marketplaces.

We have developed and we expect to continue to develop additional services leveraging our centralized database and 3D digital twin technology to meet the needs of our existing customers as well as potential new categories of customers.

Our services are typically distributed to our customers under subscription-based license agreements that generally renew automatically, a majority of which have a term of at least one year.

Upon renewal, many of the subscription contract rates may change in accordance with contract provisions or as a result of contract renegotiations.

To encourage customers to use our

services regularly, we generally charge a fixed monthly amount for our subscription-based services rather than charging fees based on actual platform usage or number of paid clicks.

Depending on the type of service, contract rates are generally based on the number of sites, number of users, organization size, the customer’s business focus, the customer's geographic location, the number of properties reported on or analyzed, the number and types of services to which a customer subscribes, the number of digital twins hosted, the number of properties a customer advertises, and the prominence and placement of a customer's advertised properties in the search results.

Our subscription customers generally pay contract fees on a monthly basis, but in some cases may pay us on a quarterly or annual basis.

Our transaction-based services primarily consist of (i) providing premium listings for individual properties on our marketplaces, (ii) providing data capture services to create digital twins, (iii) the sale of Matterport cameras and capture equipment, and (iv) Ten-X auction fees.

*Commercial Real Estate*

CoStar also provides benchmarking for the hospitality industry under the STR brand, lease analytical capabilities, and risk management and other debt solutions for lenders.

With the Domain Acquisition, we also offer commercial real estate listings in Australia.

*Other Commercial Real Estate*

Matterport primarily provides hosting services for its 3D digital twins on a subscription basis.

Matterport also provides capture services of spatial data and other add-on services to existing subscription customers and sells 3D capture cameras and accessories.

*Residential Real Estate*

Our flagship brands in the U.S. are Apartments.com, Homes.com, and Land.com.

Apartments.com and Land.com provide comprehensive advertising on a subscription basis.

Domain and OnTheMarket are our primary brands in Australia and the U.K., respectively.

Domain primarily provides agents premium listings on a transactional basis.

We expect Residential Real Estate's revenue growth rate for the year ending December 31, 2026 to accelerate compared to the revenue growth rate for the year ended December 31, 2025, due to a full year's benefit of the Domain Acquisition completed in August 2025 and an increase in the number of Homes.com members.

Contract renewal rates are calculated on all subscription-based contracts with a term of at least one year.

- Integration of our residential platforms.

Deploying Homes.com in Australia and the U.K. through the integrations of our Domain and OnTheMarket businesses.

Leveraging rentals marketing and lead generation across platforms, in particular, Apartments.com and Homes.com.

Scaling Homes.com through new product releases including depth advertising and the new homes builder program.

Continue to develop new and improved tools for residential agents and brokers to help amplify their reach.

- Launching additional AI-enabled features across our products.

*Information Services*

We provide real estate and lease management technology solutions, including lease administration, lease accounting, transaction management, and professional services through our CoStar Real Estate Manager and Visual Lease service offerings.

We also provide data and reports on an ad hoc basis to customers in the hospitality industry.

We expect Information Services' revenue growth rate for the year ending December 31, 2025 to accelerate compared to the revenue growth rate for the year ended December 31, 2024 as a result of the Visual Lease Acquisition.

*Multifamily*

Apartments.com is the flagship brand of our apartment marketing network of subscription-based advertising services and provides property management companies and landlords with a comprehensive advertising destination for their available rental units.

In addition, it offers renters a platform for searching for available rentals and earns transaction-based revenue primarily from providing online tenant applications, including background and credit checks, and rental payment processing.

We expect Multifamily's revenue growth rate for the year ending December 31, 2025 to moderate compared to the revenue growth rate for the year ended December 31, 2024, due to the impact in 2025 of pivoting the Apartments.com sales force to support the Homes.com product launch in 2024.

We expect LoopNet's revenue growth rate for the year ending December 31, 2025 to be consistent with the revenue growth rate for the year ended December 31, 2024.

*Residential*

We expect Residential's revenues for the year ending December 31, 2025 to increase, but at a slower rate, compared to the year ended December 31, 2024 due to additional sales of our Homes.com memberships.

*Other Marketplaces*

We expect Other Marketplaces' revenues for the year ending December 31, 2025 to increase compared to the revenues for the year ended December 31, 2024 due to increased revenues from our Land.com and BizBuySell Networks.

We generally see higher net new bookings of Apartments.com listing services during the peak summer rental season and higher CoStar net new bookings towards the end of the year; however, sales fluctuate from year-to-year and revenue is not generally seasonal because our services are typically sold on a subscription basis.

The increase in the percentage of our revenues from subscription-based contracts from 2023 to 2024 was due to increased sales in our Multifamily products.

- Continuing to invest in and develop Homes.com.

In 2024, we launched Homes.com memberships giving real estate agents the ability to advertise and promote their listings on our website featuring original, media rich content.

In 2025, we plan to continue hiring our dedicated Homes.com sales force.

We plan to continue to raise unaided brand awareness of the site through targeted marketing campaigns and to continue to focus on attracting recurring visitors to the site.

In addition, we plan to develop and market additional products.

- Continuing to expand our CoStar and LoopNet products internationally.

We continue to increase our international research team to collect data in European markets.

- Using the aggregate and anonymized data from leases within CoStar Real Estate Manager and Visual Lease to create a trusted source of pricing and occupancy information for Commercial Real Estate.

We expect our investment in the sales force will increase our selling and marketing expenses for the year ending December 31, 2025 compared to the year ended December 31, 2024.

We intend to continue to assess the need for additional investments in

| Revenues | | | $ | 2,736.2 | | | | | 100 | | % | | | | $ | 2,455.0 | | | | | 100 | | % | | | | $ | 2,182.4 | | | | | 100 | | % |

| Cost of revenues | | | 558.5 | | | | | | 20 | | | | | | 491.5 | | | | | | 20 | | | | | | 414.0 | | | | | | 19 | | |

| Gross profit | | | 2,177.7 | | | | | | 80 | | | | | | 1,963.5 | | | | | | 80 | | | | | | 1,768.4 | | | | | | 81 | | |

| Software development | | | 325.3 | | | | | | 12 | | | | | | 267.6 | | | | | | 11 | | | | | | 220.9 | | | | | | 10 | | |

| General and administrative | | | 439.1 | | | | | | 16 | | | | | | 381.5 | | | | | | 16 | | | | | | 338.7 | | | | | | 16 | | |

| Total operating expenses(1) | | | 2,173.0 | | | | | | 79 | | | | | | 1,681.2 | | | | | | 68 | | | | | | 1,317.4 | | | | | | 60 | | |

| Interest income, net | | | 212.5 | | | | | | 8 | | | | | | 213.6 | | | | | | 9 | | | | | | 32.1 | | | | | | 1 | | |

| Income before income taxes(1) | | | 210.1 | | | | | | 8 | | | | | | 501.3 | | | | | | 20 | | | | | | 486.5 | | | | | | 22 | | |

| Net income(1) | | | $ | 138.7 | | | | | 5 | | % | | | | $ | 374.7 | | | | | 15 | | % | | | | $ | 369.5 | | | | | 17 | | % |

| CoStar | | | $ | 1,020.5 | | | | | 37 | | % | | | | $ | 925.2 | | | | | 38 | | % | | | | $ | 837.0 | | | | | 38 | | % |

| Information services | | | 135.9 | | | | | | 5 | | | | | | 170.9 | | | | | | 7 | | | | | | 157.4 | | | | | | 7 | | |

| Multifamily | | | 1,067.3 | | | | | | 39 | | | | | | 914.2 | | | | | | 37 | | | | | | 745.4 | | | | | | 34 | | |

| LoopNet | | | 281.7 | | | | | | 10 | | | | | | 264.8 | | | | | | 11 | | | | | | 230.9 | | | | | | 11 | | |

| Residential | | | 100.6 | | | | | | 4 | | | | | | 46.1 | | | | | | 2 | | | | | | 73.7 | | | | | | 3 | | |

| Other marketplaces | | | 130.2 | | | | | | 5 | | | | | | 133.8 | | | | | | 5 | | | | | | 138.0 | | | | | | 6 | | |

We provide [removed: online marketplace services,] information, [added: analytics,] and [removed: analytics] [added: online marketplace services] to [removed: commercial] real estate and related business communities within the regions where we [removed: operate] [added: operate,] which primarily [removed: include,] [added: include] North America, [removed: Europe,] Asia-Pacific, [added: Europe,] and Latin America.

The functional currency for a majority of our operations is the local currency, with the exception of certain international locations for which the functional currency is the British [removed: Pound.][added: Pound or U.S. Dollar.]

Fluctuations in the British Pound, Canadian [removed: dollar] [added: Dollar, Australian Dollar,] and Euro may have an impact on our business, results of operations, and financial position.

For the years ended December 31, [removed: 2024] [added: 2025] and December 31, [removed: 2023, revenues] [added: 2024, revenue] denominated in foreign currencies were approximately [removed: 5%] [added: 9%] and [removed: 4%] [added: 5%] of total revenue, respectively.

For the years ended December 31, [removed: 2024] [added: 2025] and December 31, [removed: 2023,] [added: 2024,] our [removed: revenues] [added: revenue] would have decreased by approximately [removed: $14] [added: $29] million and [removed: $10] [added: $14] million, respectively, if the U.S. dollar exchange rate used strengthened by 10%.

For the years ended December 31, [removed: 2024] [added: 2025] and December 31, [removed: 2023,] [added: 2024,] our [removed: revenues] [added: revenue] would have increased by approximately [removed: $14] [added: $29] million and [removed: $10] [added: $14] million, respectively, if the U.S. dollar exchange rate used weakened by 10%.

As of December 31, [removed: 2024,] [added: 2025,] accumulated other comprehensive loss included a [removed: loss] [added: gain] from foreign currency translation adjustments of approximately [removed: $25.5] [added: $80] million.

We do not believe we have material exposure to market risks associated with changes in interest rates related to cash equivalent securities held as of December 31, [removed: 2024.][added: 2025.]

Changes in interest rates would not have a material impact to our current interest and debt financing expense, as all of our borrowings except for our credit facility are fixed rate, and no amounts were outstanding under our credit facility as of December 31, [removed: 2024.][added: 2025.]

See Note [removed: 11] [added: 10] of the Notes to the Consolidated Financial Statements included in Part IV of this Report for additional information regarding our 2024 Credit Agreement.

We had approximately [removed: $3.0] [added: $6.7] billion of goodwill and intangible assets as of December 31, [removed: 2024.][added: 2025.]

As of December 31, [removed: 2024,] [added: 2025,] we believe our intangible assets will be recoverable; however, changes in the economy, the [removed: business] [added: industry] in which we [removed: operate] [added: operate,] and our own relative performance could change the assumptions used to evaluate intangible asset recoverability.

In the event that we determine that an asset has been impaired, we would recognize an impairment charge equal to the amount by which the carrying amount of the [removed: assets] [added: asset] exceeds [removed: the] [added: its] fair [removed: value of the asset.][added: value.]

As of December 31, 2025, we had $1.7 billion of cash, cash equivalents,

and restricted cash.

Fluctuations in the exchange rates of revenues denominated in any other foreign currencies would have had an immaterial impact on our consolidated results.

We currently

do not use financial instruments to hedge our exposure to exchange rate fluctuations with respect to our foreign subsidiaries.

We may seek to enter into hedging transactions in the future to reduce our exposure to exchange rate fluctuations, but we may be unable to enter into hedging transactions successfully, on acceptable terms or at all.

As of December 31, 2024, we had $4.7 billion of cash and cash equivalents.

In this Report, the words “we,” “our,” “us,” “CoStar Group,” or the “Company” refer to CoStar Group, Inc. and its direct and indirect [removed: wholly owned] [added: wholly-owned] subsidiaries.

We [removed: own and operate leading online marketplaces for real estate in the U.S. and the U.K., based on the numbers of unique visitors and site visits per month;] provide more information, analytics, and marketing services than many of our competitors; offer the most comprehensive commercial real estate database available; and have the largest commercial real estate research department in the industry.

Over time, we have [removed: expanded,] [added: expanded] and [removed: we] continue to [removed: expand,] [added: expand] our services for real estate online marketplaces, information, [added: analytics,] and [removed: analytics to continue] [added: 3D digital twin technology] to [removed: meet] [added: address] the [added: evolving] needs of the industry as it grows and evolves.

Our standardized platform includes the most comprehensive proprietary database of commercial real estate information in the industry; the largest research department in the commercial real estate industry; proprietary data collection, information management, and quality control systems; a large in-house product development team; a broad suite of web-based information, analytics, and online marketplace services; a large team of analysts and economists; risk management tools; [added: 3D digital twin technology in the property markets;] and a large, diverse base of clients.

We have spent more than 35 years building and acquiring databases of real estate information, which includes information on homes, [removed: school,] [added: schools,] communities, commercial properties, leasing, sales, comparable sales, tenants, and demand statistics, as well as digital images, drone videos, and [removed: 3-D] [added: 3D] tours, [removed: plat] [added: plot] maps, and floor plans.

[removed: This highly complex database is comprised of] hundreds of data fields, tracking such categories as location, site and zoning information, building characteristics, space and unit characteristics and availability, tax assessments, true ownership, sales and lease comparables, residential rents, vacancies and concessions, space requirements, retail locations, mortgage and deed information, for-sale and for-lease listings, fund data, income and expense histories, tenant names, tenant credit scores, view of company locations, lease expirations, contact information, historical trends, forecasts, and demographic information.

We also operate complementary online marketplaces for commercial and residential real estate [removed: listings and] [added: listings,] apartment rentals, [added: land for sale, and business for sale,] as well as a commercial real estate auction platform.

We have also set up direct feeds from larger apartment sites, owners, [added: brokers,] and [removed: brokers.][added: home builders.]

Our field research efforts include physical inspections of properties to research new availabilities, find additional property inventory, identify new construction, collect tenant information, verify existing information, photograph properties, and create high quality videos of interior spaces (including walk-through videos and [removed: 3-D] [added: Matterport 3D] virtual tours), amenities, and exterior features of properties.

A typical site inspection of a commercial property consists of photographing the building, capturing interior images, videos, and [removed: 3-D] [added: Matterport 3D] tours, measuring the building, geo-coding the building, capturing “for-sale” or “for-lease” sign information, counting parking spaces, assessing property condition and construction, and gathering tenant information.

We are leveraging our capabilities developed from our extensive commercial real estate research efforts to produce original, media rich content of neighborhoods, schools, parks, [removed: and] [added: new home communities,] condominium buildings' amenities, and common areas for our residential [removed: products using professional photographers and a fleet of drones to conduct aerial research of residential real estate.][added: products.]

Licensing agreements with these entities allow us to use a variety of commercial real estate information, including property ownership, tenant information, demographic information, maps, [added: and] aerial photographs, [removed: and 3-D virtual apartment tours of apartment communities,] all of which enhance our services.

Our [removed: principal online] [added: Commercial Real Estate segment offers] commercial real estate information and [removed: analytics services and] [added: analytics,] online [removed: marketplaces] [added: marketplaces, and 3D digital twin technology and its principal brands] are:

CoStar offers [removed: a] subscription-based [added: access to our] platform [removed: for] [added: of] commercial real estate intelligence with several key features:

[removed: *•Properties*] [added: *•Properties -*] Provides a comprehensive inventory of various property types, including office, industrial, retail, multifamily, hospitality, student housing, and land.

- [removed: *Leasing*] [added: *Leasing -*] Offers data on lease transactions and tools to manage user-entered lease data.

- [removed: *Sales*] [added: *Sales -*] A database of commercial real estate sales transactions, useful for researching property comparables, identifying market trends, expediting appraisals, and supporting property valuations.

- [removed: *Tenants*] [added: *Tenants -*] Provides detailed tenant information, including lease expirations, occupancy levels, and growth rates, allowing users to target prospective clients.

- *Owners* [added: -] Provides detailed portfolio information, including lease expirations, occupancy levels, and growth rates, allowing users to target prospective clients.

- *Markets* [added: -] Enables viewing and reporting on market and submarket trends, including leasing, vacancy, rental rates, construction, investment sales, and economic conditions.

- [removed: *Benchmarking*] [added: *STR Benchmarking* -] Provides hospitality benchmarking, allowing hotels to measure performance against competitors based on occupancy, ADR, and RevPAR.

- [removed: *Lender* Tools] [added: *Debt Solutions* - Provides tools] for lenders to manage loan portfolios and risk, including portfolio surveillance, concentration risk monitoring, stress testing, and expected credit loss modeling.

We [added: also offer SaaS platforms and related professional services under the CoStar Real Estate Manager and Visual Lease brands which] provide real estate and lease management technology [removed: solutions, including] [added: solutions for] lease administration, lease accounting, and [removed: abstraction services, through our CoStar Real Estate Manager service and the Visual Lease Acquisition.][added: transaction management.]

[removed: Apartments.com,] [added: Apartments.com is] the flagship brand of our network of apartment marketing [removed: sites, provides a variety of subscription-based ad packages and enhancements that] [added: sites which] allow property [removed: managers and] owners [added: and managers] to showcase their apartment community through increased exposure and [added: media rich] interactions that allow renters to view, engage, and connect with the community.

[removed: LoopNet.com,] [added: LoopNet,] the flagship brand of our network of commercial property marketing sites, is a top commercial real estate marketing site where property owners, landlords, and brokers can advertise properties for sale or lease on a site that supplements their listing with CoStar Group's database of property information and content.

[removed: Our] [added: - Ten-X is a commercial real estate auction] platform [removed: provides] [added: providing] brokers, sellers, and buyers access to data-driven technology and marketing tools to expand market visibility and decrease time to close.

To encourage [removed: clients to] [added: regular] use [added: of] our [removed: services regularly,] [added: services,] we generally charge a fixed monthly [removed: amount for our subscription-based services] [added: subscription fee] rather than [removed: charging] fees based on actual platform usage or number of paid clicks.

Depending on the type of service, contract rates are generally based on the number of sites, number of users, organization size, the client's business focus, the client's geographic location, the number [added: of properties reported on or analyzed, the number] and types of services to which a client subscribes, the number of [added: digital twins hosted, the number of] properties a [removed: client] [added: customer] advertises, and the prominence and placement of a [removed: client's] [added: customer's] advertised properties in the search results.

Our subscription [removed: clients] [added: customers] generally pay contract fees on a monthly basis, but in some cases may pay us on a quarterly or annual basis.

Our transaction-based services primarily consist of [added: (1) providing premium listings for individual properties on our marketplaces, (ii) providing data capture services to create digital twins, (iii) the sale of Matterport cameras and capture equipment, and (iv)] auction fees from our Ten-X online auction platform for commercial real estate, which are generally calculated as a percentage of the final sales price for the commercial real estate property sold and recognized as revenue upon the successful [removed: closure] [added: closing] of [removed: an auction.][added: the sale of the auctioned property.]

A large number of parties involved in commercial and residential real estate [added: industries] and the related business community use the services [removed: we provide] to obtain information [removed: they need] [added: needed] to conduct their businesses, including:

| • | | | Sales and leasing brokers | | | • | | | [removed: Government agencies] [added: Pension fund managers] | | |

| • | | | [removed: Property owners] [added: Real estate agents] | | | • | | | Mortgage-backed security issuers | | |

| • | | | Property managers | | | • | | | [removed: Appraisers] [added: Reporters] | | |

| • | | | Design and construction professionals | | | • | | | [removed: Pension fund managers] [added: Building services vendors] | | |

| • | | | Real estate developers | | | • | | | [removed: Reporters] [added: Appraisers] | | |

| • | | | Real estate investment trust managers | | | • | | | [removed: Tenant vendors] [added: Communications providers] | | |

| • | | | Investment and commercial bankers | | | • | | | [removed: Building services vendors] [added: Insurance companies’ managers] | | |

| • | | | [removed: Retailers] [added: Mortgage bankers] | | | • | | | Institutional advisors | | |

| • | | | [removed: Hospitality owners] [added: Mortgage brokers] | | | • | | | Investors and asset managers | | |

CoStar Group is a leading provider of online real estate marketplaces, information, analytics, and 3D digital twin technology in the property markets.

We own and operate leading online marketplaces for real estate in the U.S., Australia, Europe, Canada, and Asia-Pacific based on the numbers of unique visitors and site visits per month.

This highly complex database is comprised of

We have developed and we expect to continue to develop additional services leveraging our centralized database and 3D digital twin technology to meet the needs of our existing customers as well as potential new categories of customers.

We also continue to leverage AI by deeply integrating it into our products and internal processes.

AI is driving research efficiencies, improving data quality and increasing the pace of product development.

We also use advanced technology, including AI, to improve how we collect and validate data and enhance the capabilities and insights we deliver to clients.

Our proprietary content is delivered at scale through a single integrated platform.

Proprietary data, an integrated delivery platform and bespoke research processes underpin our product solutions.

We use advanced technology, including AI, to improve data collection, data generation and data quality.

We operate, develop products, and deliver our services in two reportable segments, Commercial Real Estate and Residential Real Estate.

With the Domain Acquisition, we also offer commercial real estate listings in Australia.

*Other Commercial Real Estate Offerings*

Our other Commercial Real Estate Offerings include:

- Matterport's 3D digital twins allow users to capture and share spaces in immersive 3D and access AI powered property insights.

These services are sold on a subscription basis.

Matterport also provides capture services of spatial data and other add-on services to existing subscription customers and sells 3D capture cameras and third-party capture devices to customers.

Residential Real Estate

Our residential marketplaces aggregate consumer demand for homes that they can rent or buy and we sell marketing and leads to the agents, owners, landlords, and property management companies that need to reach those consumers with their offerings.

Our flagship brands in the U.S. are Apartments.com, Homes.com, and Land.com.

Homes.com allows property owners and real estate agents to reach renters and buyers on a your-listing your lead basis.

Powered by Homes AI, consumers can find their dream home by engaging in natural, real-time, two-way conversations - by voice or text - to search, refine, and explore homes in an interactive experience that feels less like navigating a website and more like being guided by a deeply knowledgeable, trusted real estate advisor.

Homes AI draws from our unmatched depth of property data, Matterport 3D digital twin technology, images, proprietary school data, neighborhood insights, and market intelligence to deliver bespoke guidance that empowers shoppers with the resources and confidence they need to find the perfect home.

Land.com is a premier marketplace to discover, buy, and sell rural real estate.

Properties listed include farms, ranches, timberland, hunting land, mountain property, lake houses, river homes, beachfront homes and country homes on acreage.

Domain and OnTheMarket are our leading marketplaces in Australia and the U.K., respectively allowing real estate agents to advertise their listings.

Customers

| • | | | Property owners | | | • | | | Government agencies | | |

| • | | | Hospitality owners | | | • | | | Tenant vendors | | |

| • | | | Retailers | | | | | | | | |

In 2025, we implemented targeted sales and marketing campaigns aimed at agents, brokers, property owners, investors, corporate and retail tenants and occupiers, as well as financial institutions and lenders in the United States, and will continue these efforts into 2026.

We acquired Visual Lease, Matterport, and Domain in November 2024, February 2025, and August 2025, respectively.

Segment Reporting

During the fourth quarter of 2025, we changed the composition of our segments from geography-based to product portfolio-based discussed under our Services above.

This change aligns with the internal reporting used by the CODM to allocate resources and assess the performance of the business.

- Capital resources;

- Quality and size of real, authenticated and intent-driven unique platform visitors; and

- Use of AI both in our products and in our internal operations.

Generally, as markets for real estate-focused online marketplaces, information, and analytics develop, additional competitors

We currently have over 100 issued patents, with 96 of those issued in the United States.

CoStar Group is a global leader of commercial and residential real estate information, analytics, and online marketplaces.

Our major brands include CoStar, a leading global provider of commercial real estate data, analytics and news; Apartments.com, a leading platform for apartment rentals, based on total revenue; LoopNet, the most trafficked commercial real estate marketplace; and Homes.com, the fastest-growing residential real estate marketplace, based on traffic.

CoStar Group’s industry-leading brands include STR, a global leader in hospitality data and benchmarking, Ten-X, an online platform for commercial real estate auctions and negotiated bids and OnTheMarket, a leading residential property portal in the U.K.

We also utilize a low-flying airplane and a fleet of drones to conduct aerial research of commercial real estate.

We place researchers on the low-flying aircraft to scout new commercial developments and take aerial photographs and videos.

*Information Services*

We provide information services internationally, through our Business Immo, Belbex, and Thomas Daily brands in France, Spain, and Germany, respectively.

*Multifamily*

Apartments.com also provides tools to facilitate the rental process, including online tenant applications with background and credit checks, and rental payment processing.

Users can also access industry news from LoopNet’s editorial team as they search for properties.

We provide commercial real estate marketing sites internationally through the following brands LoopNet.co.uk in the U.K., BureauxLocaux in France, and Belbex.com in Spain.

*Residential*

Homes.com and the acquisition of OnTheMarket have enabled us to expand our offerings to the residential for sale market.

Homes.com is a homes for sale listings site that combines our proprietary research with listing information to allow homebuyers an informative and collaborative experience finding homes for sale or lease.

In February 2024, we began selling Homes.com memberships, which are subscription-based advertising services promoting an agent's profile and listings on our website.

OnTheMarket is a property portal in the U.K. which primarily offers subscriptions-based advertising services to agents.

*Other Marketplaces*

- *Ten-X* is an online auction platform for commercial real estate.

The platform allows brokers and sellers to onboard assets, evaluate the results of complimentary marketing campaigns, and follow up on pre-qualified leads.

Buyers can search for properties that meet their investment goals and are given access to market analysis and due diligence documents.

- Land.com is a marketplace for rural land sales, where sellers pay to list their land and buyers can search listings.

Clients

| • | | | Mortgage bankers | | | • | | | Communications providers | | |

| • | | | Mortgage brokers | | | • | | | Insurance companies’ managers | | |

In 2024, we implemented sales initiatives targeting agents, brokers, property owners, and lenders in the U.S., continuing this focus into 2025.

We acquired Business Immo, OnTheMarket, and Visual Lease in April 2022, December 2023, and November 2024, respectively.

Segments

Our chief executive officer, who acts as the CODM, makes operating decisions and evaluates operating performance on the basis of our business geographically.

We operate in two reportable segments which are North America, which includes the U.S. and Canada, and International, which primarily includes Europe, Asia-Pacific, and Latin America.

Information about risks associated with our foreign operations is included in “Item 1A.

Risk Factors” and “Item 7A.

Quantitative and Qualitative Disclosures about Market Risk” in this Report.

- Capital resources.

We currently have seven patents in Canada, which expire in 2033 (1 patent), 2035 (2 patents), and 2036 (4 patents), covering, among other things, certain features of our field research methodologies and user interface features, and 12 patents in the U.S. which expire in 2025 (1 patent), 2032 (2 patents), 2036 (4 patents), 2037 (4 patents), and 2038 (1 patent), covering, among other things, certain features of our field research methodologies and user interface feature.

As of January 31, 2025, we employed 6,593 employees.

U.S.-based employees represent approximately 88% of the overall employee population, followed by 10% in European, Asia-Pacific, and Latin American countries, and 2% in Canada.

None of our employees are represented by a labor union.

We have experienced no work stoppages.

We believe that diverse teams deliver better and more innovative solutions.

We also develop various programming communications and training to help foster an inclusive environment for individuals regardless of background.

Currently, and from time to time, we are involved in litigation incidental to the conduct of our business, including, among others, the legal actions discussed under “Contingencies” in Note [removed: 13] [added: 12] “Commitments and Contingencies” of the Notes to our Consolidated Financial Statements included in Part IV of this Report.

For the fiscal year ended December 31, [removed: 2024][added: 2025]

[removed: ][added: ]

As of June 30, [removed: 2024,] [added: 2025,] the aggregate market value of the common stock (based upon the closing price of the stock on the Nasdaq Global Select Market) of the registrant held by non-affiliates was approximately [removed: $30.1] [added: $33.9] billion.

As of February [removed: 13, 2025, 410,125,610] [added: 20, 2026, 419,793,301] shares of common stock were outstanding.

Portions of the registrant’s definitive proxy statement, which is expected to be filed with the Securities and Exchange Commission within 120 days after the end of the registrant’s fiscal year ended December 31, [removed: 2024] [added: 2025] are incorporated by reference into Part III of this Report.

| | | | [Glossary of [removed: Terms](#i41275714db3541c8a24982c2435763d8_13)] [added: Terms](#ib08faba301d94dee895ca69fb9a28832_13)] | | | [removed: [4](#i41275714db3541c8a24982c2435763d8_13)] [added: [4](#ib08faba301d94dee895ca69fb9a28832_13)] | | |

| Item 1. | | | [removed: [Business](#i41275714db3541c8a24982c2435763d8_19)] [added: [Business](#ib08faba301d94dee895ca69fb9a28832_19)] | | | [removed: [8](#i41275714db3541c8a24982c2435763d8_19)] [added: [8](#ib08faba301d94dee895ca69fb9a28832_19)] | | |

| Item 1A. | | | [Risk [removed: Factors](#i41275714db3541c8a24982c2435763d8_22)] [added: Factors](#ib08faba301d94dee895ca69fb9a28832_22)] | | | [removed: [16](#i41275714db3541c8a24982c2435763d8_22)] [added: [16](#ib08faba301d94dee895ca69fb9a28832_22)] | | |

| Item 1B. | | | [Unresolved Staff [removed: Comments](#i41275714db3541c8a24982c2435763d8_25)] [added: Comments](#ib08faba301d94dee895ca69fb9a28832_25)] | | | [removed: [31](#i41275714db3541c8a24982c2435763d8_25)] [added: [34](#ib08faba301d94dee895ca69fb9a28832_25)] | | |

| Item 1C. | | | [removed: [Cybersecurity](#i41275714db3541c8a24982c2435763d8_28)] [added: [Cybersecurity](#ib08faba301d94dee895ca69fb9a28832_28)] | | | [removed: [31](#i41275714db3541c8a24982c2435763d8_28)] [added: [34](#ib08faba301d94dee895ca69fb9a28832_28)] | | |

| Item 2. | | | [removed: [Properties](#i41275714db3541c8a24982c2435763d8_31)] [added: [Properties](#ib08faba301d94dee895ca69fb9a28832_31)] | | | [removed: [33](#i41275714db3541c8a24982c2435763d8_31)] [added: [36](#ib08faba301d94dee895ca69fb9a28832_31)] | | |

| Item 3. | | | [Legal [removed: Proceedings](#i41275714db3541c8a24982c2435763d8_34)] [added: Proceedings](#ib08faba301d94dee895ca69fb9a28832_34)] | | | [removed: [33](#i41275714db3541c8a24982c2435763d8_34)] [added: [36](#ib08faba301d94dee895ca69fb9a28832_34)] | | |

| Item 4. | | | [Mine Safety [removed: Disclosures](#i41275714db3541c8a24982c2435763d8_37)] [added: Disclosures](#ib08faba301d94dee895ca69fb9a28832_37)] | | | [removed: [33](#i41275714db3541c8a24982c2435763d8_37)] [added: [36](#ib08faba301d94dee895ca69fb9a28832_37)] | | |

| Item 5. | | | [Market for Registrant’s Common Equity, Related Stockholder [removed: Matters] [added: Matters,] and Issuer Purchases of Equity [removed: Securities](#i41275714db3541c8a24982c2435763d8_43)] [added: Securities](#ib08faba301d94dee895ca69fb9a28832_43)] | | | [removed: [33](#i41275714db3541c8a24982c2435763d8_43)] [added: [36](#ib08faba301d94dee895ca69fb9a28832_43)] | | |

| Item 6. | | | [removed: [Reserved](#i41275714db3541c8a24982c2435763d8_46)] [added: [Reserved](#ib08faba301d94dee895ca69fb9a28832_46)] | | | [removed: [35](#i41275714db3541c8a24982c2435763d8_46)] [added: [38](#ib08faba301d94dee895ca69fb9a28832_46)] | | |

| Item 7. | | | [Management’s Discussion and Analysis of Financial Condition and Results of [removed: Operations](#i41275714db3541c8a24982c2435763d8_49)] [added: Operations](#ib08faba301d94dee895ca69fb9a28832_49)] | | | [removed: [35](#i41275714db3541c8a24982c2435763d8_49)] [added: [38](#ib08faba301d94dee895ca69fb9a28832_49)] | | |

| Item 7A. | | | [Quantitative and Qualitative Disclosures about Market [removed: Risk](#i41275714db3541c8a24982c2435763d8_85)] [added: Risk](#ib08faba301d94dee895ca69fb9a28832_82)] | | | [removed: [47](#i41275714db3541c8a24982c2435763d8_85)] [added: [51](#ib08faba301d94dee895ca69fb9a28832_82)] | | |

| Item 8. | | | [Financial Statements and Supplementary [removed: Data](#i41275714db3541c8a24982c2435763d8_88)] [added: Data](#ib08faba301d94dee895ca69fb9a28832_85)] | | | [removed: [48](#i41275714db3541c8a24982c2435763d8_88)] [added: [52](#ib08faba301d94dee895ca69fb9a28832_85)] | | |

| Item 9. | | | [Changes in and Disagreements with Accountants on Accounting and Financial [removed: Disclosure](#i41275714db3541c8a24982c2435763d8_91)] [added: Disclosure](#ib08faba301d94dee895ca69fb9a28832_88)] | | | [removed: [48](#i41275714db3541c8a24982c2435763d8_91)] [added: [52](#ib08faba301d94dee895ca69fb9a28832_88)] | | |

| Item 9A. | | | [Controls and [removed: Procedures](#i41275714db3541c8a24982c2435763d8_94)] [added: Procedures](#ib08faba301d94dee895ca69fb9a28832_91)] | | | [removed: [48](#i41275714db3541c8a24982c2435763d8_94)] [added: [52](#ib08faba301d94dee895ca69fb9a28832_91)] | | |

| Item 9B. | | | [Other [removed: Information](#i41275714db3541c8a24982c2435763d8_97)] [added: Information](#ib08faba301d94dee895ca69fb9a28832_94)] | | | [removed: [49](#i41275714db3541c8a24982c2435763d8_97)] [added: [53](#ib08faba301d94dee895ca69fb9a28832_94)] | | |

| Item 9C. | | | [Disclosure Regarding Foreign Jurisdictions that Prevent [removed: Inspections](#i41275714db3541c8a24982c2435763d8_100)] [added: Inspections](#ib08faba301d94dee895ca69fb9a28832_97)] | | | [removed: [49](#i41275714db3541c8a24982c2435763d8_97)] [added: [53](#ib08faba301d94dee895ca69fb9a28832_94)] | | |

| Item 10. | | | [Directors, Executive [removed: Officers] [added: Officers,] and Corporate [removed: Governance](#i41275714db3541c8a24982c2435763d8_106)] [added: Governance](#ib08faba301d94dee895ca69fb9a28832_103)] | | | [removed: [50](#i41275714db3541c8a24982c2435763d8_106)] [added: [54](#ib08faba301d94dee895ca69fb9a28832_103)] | | |

| Item 11. | | | [Executive [removed: Compensation](#i41275714db3541c8a24982c2435763d8_109)] [added: Compensation](#ib08faba301d94dee895ca69fb9a28832_106)] | | | [removed: [50](#i41275714db3541c8a24982c2435763d8_109)] [added: [54](#ib08faba301d94dee895ca69fb9a28832_106)] | | |

| Item 12. | | | [Security Ownership of Certain Beneficial Owners and Management and Related Stockholder [removed: Matters](#i41275714db3541c8a24982c2435763d8_112)] [added: Matters](#ib08faba301d94dee895ca69fb9a28832_109)] | | | [removed: [50](#i41275714db3541c8a24982c2435763d8_112)] [added: [54](#ib08faba301d94dee895ca69fb9a28832_109)] | | |

| Item 13. | | | [Certain Relationships and Related Transactions, and Director [removed: Independence](#i41275714db3541c8a24982c2435763d8_115)] [added: Independence](#ib08faba301d94dee895ca69fb9a28832_112)] | | | [removed: [50](#i41275714db3541c8a24982c2435763d8_115)] [added: [54](#ib08faba301d94dee895ca69fb9a28832_112)] | | |

| Item 14. | | | [Principal Accountant Fees and [removed: Services](#i41275714db3541c8a24982c2435763d8_118)] [added: Services](#ib08faba301d94dee895ca69fb9a28832_115)] | | | [removed: [50](#i41275714db3541c8a24982c2435763d8_118)] [added: [54](#ib08faba301d94dee895ca69fb9a28832_115)] | | |

| Item 15. | | | [Exhibits and Financial Statement [removed: Schedules](#i41275714db3541c8a24982c2435763d8_124)] [added: Schedules](#ib08faba301d94dee895ca69fb9a28832_121)] | | | [removed: [51](#i41275714db3541c8a24982c2435763d8_124)] [added: [55](#ib08faba301d94dee895ca69fb9a28832_121)] | | |

| Item 16. | | | [Form 10-K [removed: Summary](#i41275714db3541c8a24982c2435763d8_127)] [added: Summary](#ib08faba301d94dee895ca69fb9a28832_124)] | | | [removed: [53](#i41275714db3541c8a24982c2435763d8_127)] [added: [57](#ib08faba301d94dee895ca69fb9a28832_124)] | | |

| | | | [Index to Consolidated Financial [removed: Statements](#i41275714db3541c8a24982c2435763d8_133)] [added: Statements](#ib08faba301d94dee895ca69fb9a28832_130)] | | | [removed: [F-](#i41275714db3541c8a24982c2435763d8_133)[1](#i41275714db3541c8a24982c2435763d8_133)] [added: [F-](#ib08faba301d94dee895ca69fb9a28832_130)[1](#ib08faba301d94dee895ca69fb9a28832_130)] | | |

| Apartments.com Network | | | Apartments.com, the flagship brand of our network of apartment marketing sites, and its network of rental websites including ApartmentFinder, ForRent.com®, AFTER55.com®, [removed: CorporateHousing.comTM and ForRentUniversity.com®] [added: CorporateHousing.comTM, ForRentUniversity.com®,] ApartmentHomeLiving.com, Apartamentos.comTM, WestsideRentals.com®, and Off Campus Partners | | |

| Audit Committee | | | The Audit Committee of the Board [added: of Directors] | | |

| BizBuySell [added: Network] | | | BizBuySell.com and its network of business for-sale websites | | |

| Board [added: of Directors] | | | The CoStar Group Board of Directors | | |

| Confidential Information | | | Information about customers, employees, contractors, suppliers, vendors, and others such as landlords and tenants, including personal information such as names, addresses, phone numbers, email addresses, credit card information, biometric data, sensitive or confidential transaction and account information, social security numbers, birthdates and financial information [added: such as trade secrets] (for example, to facilitate the apartment rental application and payment process between a renter and property manager), as well as a broad range of proprietary and confidential business information, collectively | | |

| CoStar Group (also the “Company,” “we,” [removed: “us”] [added: “us,”] or “our”) | | | The legal entity, CoStar Group, Inc., a Delaware corporation, one or more of its consolidated subsidiaries or operating segments, or the entirety of CoStar Group, Inc. and its consolidated subsidiaries | | |

| CRI | | | The legal [removed: entity,] [added: entity] CoStar Realty Information, Inc., a Delaware corporation and [removed: wholly owned] [added: wholly-owned] subsidiary [added: (and primary operating entity in the United States)] of CoStar Group, Inc. | | |

| EBITDA | | | Net income [added: (loss)] before interest income or expense, net; other income or expense, net; loss on debt extinguishment; income taxes; [removed: depreciation] [added: depreciation;] and amortization | | |

| Homes.com | | | [removed: The] [added: One of the] flagship [removed: brand] [added: brands] of our [removed: North American] residential products and a homes for-sale listings site, which manages workflow and marketing for residential real estate agents and brokers and allows homebuyers to view residential property listings, research communities, and connect with real estate agents and brokers | | |

| IT Systems | | | Information technology networks, [removed: systems] [added: systems,] and infrastructure to process, [removed: transmit] [added: transmit,] and store electronic information and to communicate among our locations around the world and with our clients and vendors, collectively | | |

| | | | [Signatures](#ib08faba301d94dee895ca69fb9a28832_127) | | | [58](#ib08faba301d94dee895ca69fb9a28832_127) | | |

| A$ | | | Australian dollars | | |

| ACC | | | Akamai Connected Cloud | | |

| AI Technologies | | | AI and machine learning technologies | | |

| AOMs | | | Structured equity vehicles operating under Domain's Agent Ownership Model. The AOMs function as strategic partnership tools that provide residential and commercial real estate agencies an economic stake in Domain-affiliated entities, creating a mechanism to reward long-term engagement and performance through profit-sharing rather than traditional commissions or rebates | | |

| ASR | | | Accelerated Share Repurchase | | |

| Assumed Matterport Plans | | | The Matterport 2021 Incentive Award Plan and Matterport, Inc. Amended and Restated 2011 Stock Incentive Plan assumed by CoStar Group in connection with the Matterport Acquisition | | |

| AWS | | | Amazon Web Services | | |

| BEAT | | | Base erosion and anti-abuse minimum tax | | |

| COSO | | | The Committee of Sponsoring Organizations of the Treadway Commission | | |

| Domain | | | Domain Holdings Australia Pty Limited | | |

| Domain Acquisition | | | CoStar's acquisition of Domain completed on August 27, 2025, pursuant to the Scheme Implementation Deed | | |

| Domain Proposal | | | The Company’s non-binding indicative proposal to acquire 100% of the issued capital of Domain by way of scheme of arrangement for a cash consideration of A$4.43 per ordinary share of Domain | | |

| Domain SID | | | The Company's binding Scheme Implementation Deed to acquire 100% of the issued capital of Domain for a cash consideration of A$4.43 per ordinary share of Domain | | |

| Domain Transaction | | | The transactions entered into by the Company to acquire Domain pursuant to the Domain SID | | |

| DSA | | | Digital Services Act | | |

| EPS | | | Earnings Per Share | | |

| EU | | | European Union | | |

| EU AI Act | | | European Union Artificial Intelligence Act | | |

| FDII | | | Foreign Derived Intangible Income | | |

| H.R.1 | | | A bill to provide for reconciliation pursuant to Title II of H. Con. Res. 14, commonly referred to as the One Big Beautiful Bill Act, signed into law on July 4, 2025 | | |

| Matterport Acquisition | | | CoStar's acquisition of Matterport completed on February 28, 2025, pursuant to the Matterport Merger Agreement | | |

| Matterport Merger Agreement | | | On April 21, 2024, CoStar entered into an Agreement and Plan of Merger and Reorganization with Matterport, Matrix Merger Sub I LLC, and Matrix Merger Sub II LLC. | | |

| NCI | | | Noncontrolling Interest | | |

| NIS 2 | | | Network and Information Security 2 Directive | | |

| OSA | | | Online Safety Act 2023 | | |

| Stock Repurchase Program | | | The stock repurchase program the Board of Directors approved in December 2025 that authorizes the repurchase of up to $1.5 billion CoStar Group Shares | | |

| VIE | | | Variable Interest Entity | | |

- the risks related to AI Technologies, such as Homes AI;

- the inability of third-party suppliers upon which Matterport relies to fulfill its needs;

- the risks related to open source software;

| | | | [Signatures](#i41275714db3541c8a24982c2435763d8_130) | | | [54](#i41275714db3541c8a24982c2435763d8_130) | | |

| Business Immo | | | The legal entity, BIH, a French société par actions simplifiée, the owner and operator of Business Immo, a leading commercial real estate news service provider in France | | |

| Business Immo Acquisition | | | CoStar UK's acquisition of the issued share capital of Business Immo on April 5, 2022 | | |

| CECL | | | Current expected credit losses | | |

| ESG | | | Environmental, Social and Governance | | |

| Homes.com Acquisition | | | CRI's acquisition of Homes.com completed on May 24, 2021 pursuant to a securities purchase agreement dated April 14, 2021 between Landmark, Homes Group, LLC and CRI | | |

| Matterport Merger Agreement | | | The Agreement and Plan of Merger dated as of April 21, 2024, by and among the Company, Matterport, Merger Sub I, and Merger Sub II, pursuant to which, among other things, and subject to its terms, (i) Merger Sub I will merge with and into Matterport (the “First Merger”), with Matterport surviving the First Merger as a wholly owned subsidiary of the Company (the “Surviving Corporation”), and (ii) in the event that the Threshold Percentage (as defined in the Matterport Merger Agreement) is at least 40%, immediately following the First Merger and as part of a single integrated transaction, the Surviving Corporation will merge with and into Merger Sub II (the “Second Merger” and, together with the First Merger, the “Mergers”), with Merger Sub II surviving the Second Merger as a wholly owned subsidiary of the Company. | | |

| Merger Sub II | | | Matrix Merger Sub II LLC, a Delaware limited liability company and wholly owned subsidiary of the Company | | |

| Neptune Merger Sub | | | Neptune V Merger Sub LLC, as Delaware limited liability company and a wholly owned subsidiary of CRI | | |

| RRSP | | | A Canadian registered retirement savings plan | | |

| Ten-X | | | The legal entity Ten-X Holding Company, Inc. and its directly and indirectly owned subsidiaries | | |

This does not imply that we meet any particular technical standards, specifications, or requirements at all [removed: times, only that] [added: times; rather,] we use the NIST CSF as a guide to help us identify, assess, and manage cybersecurity risks [removed: relevant to our business.]

Our cybersecurity risk management program is integrated into our overall [removed: enterprise] risk management [removed: program,] [added: program] and shares common methodologies, reporting channels, and governance processes that apply across the [removed: enterprise] [added: Company's] risk management [removed: program to other legal, compliance, strategic, operational, and financial risk areas.][added: program.]

e.A cybersecurity incident response plan that includes procedures for responding to cybersecurity incidents; and regular tabletop exercises to assess our response readiness; [removed: and]

f.A third-party risk management process for key service providers, suppliers, and vendors who access critical systems and data based on risk [removed: profile.][added: profile; and]

We have not identified material risks from known cybersecurity threats, including as a result of any prior cybersecurity [removed: incidents,] [added: incidents] that have materially affected [removed: us, including] our operations, business strategy, results of operations, or financial condition.

See *Risk Factors – “Cyberattacks and security vulnerabilities could result in material harm to our reputation, business, and financial condition.”* and *“Technical problems or disruptions that affect either our customers’ ability to access our services, or the software, internal applications, database, and network systems underlying our services, could damage our reputation and lead to reduced demand for our online marketplace services, information, and analytics, lower [removed: revenues] [added: revenue] and increase costs.”*

Our Board [added: of Directors] considers cybersecurity risk as part of its risk oversight function and has delegated to the Audit Committee oversight of cybersecurity and [removed: other information technology risks.][added: generative AI risks, controls, and procedures.]

Our Vice President of Cyber Security (VPCS), who reports up to the CTO, is responsible for day-to-day assessment and management of cybersecurity [removed: risk.][added: risk, including supervising both our internal cybersecurity personnel and our retained external cybersecurity consultants.]

Our Audit Committee receives reports from the CTO on our cybersecurity [removed: risks.][added: risks and our use of AI.]

The Audit Committee reports to the full Board [added: of Directors] regarding its activities, including those related to [removed: cybersecurity.][added: cybersecurity and AI.]

Our [added: CTO and VPCS assist the] management team [removed: is] [added: in staying] informed [added: about] and [removed: monitors] [added: monitoring] the prevention, detection, mitigation, and remediation of cybersecurity threats.

He holds a M.S. in information systems from George Washington University and a B.A. in computer science from State University of New [removed: York.][added: York—Geneseo.]

The CTO and VPCS are informed about and [removed: monitors] [added: monitor] the prevention, detection, mitigation, and remediation of cybersecurity risks and incidents through various means, which may include briefings from internal security personnel; threat intelligence and other information obtained from governmental, public, or private sources, including external consultants engaged by us; and alerts and reports produced by security tools deployed in the IT environment.

relevant to our business.

g.A formal information security training program for all employees.

Our CTO is also responsible for overseeing the material risks and strategic opportunities associated with AI.

The Audit Committee oversees management’s implementation of our cybersecurity risk management program.

The team has primary responsibility for our overall cybersecurity risk management program and supervises both our internal cybersecurity personnel and our retained external cybersecurity consultants.

[removed: As of] [added: On] January 21, 2025, we [removed: have] relocated our headquarters to our owned building at 1201 Wilson [removed: Blvd] [added: Blvd.,] in Arlington, Virginia, occupying approximately [removed: 160,000] [added: 198,000] square feet.

We exited our previous headquarters located at 1331 L Street, NW, in downtown Washington, D.C., with a lease that [removed: expires] [added: expired] on May 31, 2025.

[removed: Our] [added: Internationally, our] principal facility in the U.K. is located in London, where we occupy [removed: 42,000] [added: approximately 52,000] square feet of office space.

Our lease for this facility has a term ending [removed: August 31, 2025.][added: November 10, 2034.]

Our staff in Richmond, Virginia is located in an owned building at 501 S 5th Street, where we occupy approximately 310,000 square feet, an owned building located at 901 Semmes Avenue, where we occupy approximately 117,000 square [removed: feet; and] [added: feet,] leased space at 951 E Byrd St., where we occupy approximately [removed: 135,000] [added: 165,000] square [added: feet, and leased space at 901 E Byrd St., where we occupy approximately 46,000 square] feet.

We also operate certain [removed: of our] research, development, and sales functions out of additional leased office spaces in Irvine, California; San Diego, California; and Atlanta, Georgia.

These locations include, among others, the following: Nashville, Tennessee; Norfolk, Virginia; Boston, Massachusetts; New York, New York; San Francisco, California; [removed: and] Los Angeles, [added: California; and Sunnyvale,] California.

We exited our previous London location when the lease expired on August 31, 2025.

Our principal facility in Australia is located in Sydney, where we occupy approximately 95,000 square feet, with a lease term ending June 30, 2031.

Additionally, we lease space for our operations in Paris, France; Madrid, Spain; Freiburg, Germany; and Manila, Philippines.

Our headquarters is used primarily by our North America operating segment.

As part of a workforce consolidation, we signed a lease for a total of approximately 52,000 square feet in London and have begun relocating employees to the new building.

These facilities are used by our International operating segment, including our recent acquisition, OnTheMarket.

Our common stock is traded on the Nasdaq Global Select Market under the symbol “CSGP.” As of January 31, [removed: 2025,] [added: 2026,] there were [removed: 1,582] [added: 1,620] holders of record of our common stock.

We do not anticipate paying any dividends on our common stock during the foreseeable future, but intend to invest our future earnings, if any, to finance our growth [removed: or] [added: and] share repurchases.

We did not issue any unregistered securities during the year ended December 31, [removed: 2024.][added: 2025.]

The following table [removed: is a summary of] [added: summarizes] our repurchases of common stock for the quarter ended December 31, [removed: 2024:][added: 2025 (in millions, except per share data):]

| [removed: 2024] [added: 2025] | | | | | | Total Number of Shares Purchased(1) | | | | | | Average Price Paid per Share | | | | | | Total Number of Shares Purchased as Part of Publicly Announced Plans or [removed: Programs] [added: Programs(2)] | | | | | | [removed: Maximum Number] [added: Approximate Dollar Value] of Shares that May Yet Be Purchased Under [removed: the] Plans or [removed: Programs] [added: Programs(2)] | | |

(1) The number [removed: of shares purchased consists of shares of common stock] [added: includes CoStar Group Shares] tendered by employees to the Company to satisfy the employees' minimum tax withholding obligations arising as a result of vesting of restricted stock grants under the Company’s [removed: 2016] [added: 2025] Stock Incentive Plan, [removed: as amended,] [added: for] which shares were purchased by the Company based on their fair market value on the trading day immediately preceding the vesting date.

- [removed: An] [added: an] equal investment in the S&P 500 Index, [added: and]

The comparison covers the period beginning December 31, [removed: 2019] [added: 2020] and ending on December 31, [removed: 2024,] [added: 2025,] and assumes the reinvestment of any dividends.

[removed: ][added: ]

| [removed: Company] [added: Company] / [removed: Index] [added: Index] | | | | | | [removed: 12/31/19] [added: 12/31/20] | | | | | | [removed: 12/31/20] [added: 12/31/21] | | | | | | [removed: 12/31/21] [added: 12/31/22] | | | | | | [removed: 12/31/22] [added: 12/31/23] | | | | | | [removed: 12/31/23] [added: 12/31/24] | | | | | | [removed: 12/31/24] [added: 12/31/25] | | |

| October 1 through 31 | | | | | | 0.3 | | | | | | $ | 77.37 | | | | | 0.3 | | | | | | $ | 365 | |

| November 1 through 30 | | | | | | 5.0 | | | | | | $ | 67.05 | | | | | 5.0 | | | | | | $ | 29 | |

| December 1 through 31 | | | | | | 0.4 | | | | | | $ | 68.07 | | | | | 0.4 | | | | | | $ | 1,500 | |

| Total | | | | | | 5.7 | | | | | | $ | 67.61 | | | | | 5.7 | | | | | | | | |

(2) In February 2025, the Board of Directors approved the Prior Stock Repurchase Program which authorized the repurchase up to $500 million of Costar Group Shares.

During the fourth quarter of 2025, the Company repurchased 5.7 million CoStar Group Shares for an aggregate cost of $385 million under the Prior Stock Repurchase Program.

The repurchases under the Prior Stock Repurchase Agreement were completed in December 2025.

In December 2025, the Board of Directors approved a Stock Repurchase Program which authorizes, but does not obligate, the repurchase of up to $1.5 billion of CoStar Group Shares.

No shares were repurchased under the Stock Repurchase Program during the fourth quarter of 2025.

See Note 14 for further discussion regarding the Prior Stock Repurchase Program, Stock Repurchase Program, and stock repurchase activity.

| CoStar Group, Inc. | | | | | | $ | 100.00 | | | | | $ | 85.50 | | | | | $ | 83.61 | | | | | $ | 94.55 | | | | | $ | 77.45 | | | | | $ | 72.75 | |

| S&P 500 Index | | | | | | $ | 100.00 | | | | | $ | 128.71 | | | | | $ | 105.40 | | | | | $ | 133.10 | | | | | $ | 166.40 | | | | | $ | 196.16 | |

| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |

| S&P Composite 1500 Real Estate Index | | | | | | $ | 100.00 | | | | | $ | 143.17 | | | | | $ | 105.48 | | | | | $ | 117.65 | | | | | $ | 124.03 | | | | | $ | 127.95 | |

| October 1 through 31 | | | | | | 1,008 | | | | | | $ | 75.44 | | | | | — | | | | | | — | | |

| November 1 through 30 | | | | | | 556 | | | | | | $ | 73.92 | | | | | — | | | | | | — | | |

| December 1 through 31 | | | | | | 6,587 | | | | | | $ | 76.90 | | | | | — | | | | | | — | | |

| Total | | | | | | 8,151 | | | | | | $ | 76.51 | | | | | — | | | | | | — | | |

None of these share purchases were part of a publicly announced program to purchase common stock of the Company.

- An equal investment in the S&P 500 Internet Services & Infrastructure Index, and

The Company decided to begin comparing the cumulative total return on its common stock with the S&P 1500 Real Estate Index, replacing the S&P 500 Internet Services & Infrastructure Index.

The Company believes the S&P 1500 Real Estate Index provides a more accurate, diverse, and useful measure to the Company’s performance.

For transitional purposes, both indices are included in the performance graph, however, only the S&P 1500 Real Estate Index will be used in future filings.

| CoStar Group, Inc. | | | | | | $ | 100.00 | | | | | $ | 154.48 | | | | | $ | 132.09 | | | | | $ | 129.17 | | | | | $ | 146.06 | | | | | $ | 119.66 | |

| S&P 500 Index | | | | | | 100.00 | | | | | | 118.40 | | | | | | 152.39 | | | | | | 124.79 | | | | | | 157.59 | | | | | | 197.02 | | |

| S&P 500 Internet Services & Infrastructure Index | | | | | | 100.00 | | | | | | 116.09 | | | | | | 133.08 | | | | | | 102.47 | | | | | | 119.55 | | | | | | 121.05 | | |

| S&P Composite 1500 Real Estate Index | | | | | | 100.00 | | | | | | 95.75 | | | | | | 137.09 | | | | | | 101.00 | | | | | | 112.65 | | | | | | 118.76 | | |

We maintain disclosure controls and procedures [removed: that are] designed to ensure that information required to be disclosed in our reports filed or submitted under the Exchange [removed: Act, as amended,] [added: Act] is recorded, processed, summarized, and reported, within the time periods specified in the SEC’s rules and [removed: forms, and that such information is accumulated and communicated to our management, including our Chief Executive Officer and Chief Financial Officer, as appropriate, to allow for timely decisions regarding required disclosure.][added: forms.]

In designing and evaluating the disclosure controls and procedures, management [removed: recognized] [added: recognizes] that any [added: systems of] controls and procedures, no matter how well designed and operated, can provide only reasonable assurance of achieving [removed: the desired control objectives, and management is required to apply] its [removed: judgment in evaluating the cost-benefit relationship of possible controls and procedures.][added: objectives.]

As of December 31, [removed: 2024, we carried out an evaluation,] [added: 2025,] under the supervision and with the participation of our management, including our Chief Executive Officer and our Chief Financial Officer, [removed: of] [added: we evaluated] the effectiveness of [removed: the design and operation of] our disclosure controls and [removed: procedures as of the end of the fiscal year.][added: procedures.]

Based on [removed: the foregoing,] [added: this evaluation,] our Chief Executive Officer and Chief Financial Officer concluded that our disclosure controls and procedures were effective as of December 31, [removed: 2024] [added: 2025,] and were operating at a reasonable assurance level.

Consistent with [removed: any] [added: our] process [removed: change that] [added: changes,] we [removed: implement,] [added: evaluate] the design [added: and effectiveness] of the internal controls [removed: has and will continue to be evaluated for effectiveness] as part of our overall assessment of [removed: the effectiveness of our] disclosure controls and procedures.

Other than the [removed: implementation of a new financial system noted above,] [added: integration activities associated with recent acquisitions,] there [removed: have been] [added: were] no changes in our internal control over financial reporting during [removed: our] [added: the] most recent fiscal quarter that have materially affected, or are reasonably likely to materially affect our internal control over financial reporting.

Management’s [added: Annual] Report on Internal Control over Financial Reporting

Management of CoStar Group is responsible for establishing and maintaining adequate internal control over financial reporting and [removed: for the assessment of the effectiveness of internal control over financial reporting.][added: assessing its effectiveness.]

[removed: As] [added: Internal control over financial reporting, as] defined by the SEC, [removed: internal control over financial reporting] is a process designed by, or [removed: supervised by,] [added: under] the [added: supervision of, the] Company’s principal executive and principal financial [removed: officers,] [added: officers] to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements in accordance with GAAP.

[removed: The Company’s] [added: Our] internal control over financial reporting is supported by written policies and procedures, which (1) pertain to the maintenance of records that, in reasonable detail, accurately and fairly reflect [removed: the] transactions and [removed: dispositions of the Company’s assets;] [added: asset dispositions;] (2) provide reasonable assurance that transactions are recorded as necessary to permit preparation of financial statements in accordance with GAAP, and that receipts and expenditures [removed: of the Company] are [removed: being] made only in accordance with [removed: authorizations of the Company’s management] [added: management's] and [removed: directors;] [added: directors' authorization;] and (3) provide reasonable assurance regarding prevention or timely detection of unauthorized acquisition, use, or disposition of [removed: the Company’s] assets that could have a material effect on the financial statements.

Projections of any evaluation of effectiveness to future periods are subject to the risk that controls may become inadequate [removed: because of] [added: due to] changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate.

[removed: In connection with the preparation of the Company's annual financial statements, management of the Company has undertaken an assessment of] [added: Management assessed] the effectiveness of [removed: the Company’s] internal control over financial reporting as of December 31, [removed: 2024 based on] [added: 2025, using the] criteria established in [removed: Internal] [added: *Internal] Control – Integrated Framework (2013 [removed: framework)] [added: framework)*] issued by [removed: the Committee of Sponsoring Organizations of the Treadway Commission.][added: COSO.]

[removed: Management's] [added: This] assessment included [removed: an evaluation of] [added: evaluating] the design [removed: of the Company's internal control over financial reporting] and testing of the operational effectiveness of [removed: the Company's] [added: our] internal control over financial reporting.

Based on this assessment, management [removed: has] concluded that [removed: the Company's] internal control over financial reporting was effective as of December 31, [removed: 2024.][added: 2025.]

Ernst & Young LLP, [removed: the] [added: our] independent registered public accounting [removed: firm that] [added: firm,] audited the [removed: Company's] financial statements included in this [removed: report, has] [added: report and] issued an attestation report on the effectiveness of internal control over financial reporting, a copy of which is included in this Report.

As permitted by the SEC, we have elected to exclude the internal controls of [removed: this acquisition,] [added: these acquisitions,] which [removed: has] [added: have] not been integrated into our existing processes and controls, from our assessment of the effectiveness of internal control over financial reporting as of December 31, [removed: 2024.][added: 2025.]

The excluded financial position of [removed: Visual Lease] [added: Matterport and Domain collectively] represented less than [removed: 3%] [added: 5%] of our total [added: assets, excluding the preliminary value of goodwill and other intangible] assets as of December 31, [removed: 2024,] [added: 2025,] and less than [removed: 1%] [added: 10%] of our [removed: revenues and total operating costs] [added: revenue] for the year then ended.

We will include the internal controls of [removed: Visual Lease] [added: Matterport and Domain] in our assessment of the effectiveness of our internal control over financial reporting as of December 31, [removed: 2025.][added: 2026.]

These controls also are designed to ensure that such information is accumulated and communicated to our management, including our Chief Executive Officer and Chief Financial Officer, as appropriate, to allow for timely decisions regarding required disclosure.

Accordingly, management is required to apply judgment in evaluating the cost-benefit relationship of possible controls and procedures.

We are continuing to integrate the internal controls over financial reporting of recent acquisitions.

These activities may require modifications to certain processes, systems, and other components of internal controls over financial reporting.

CoStar Group completed the Matterport Acquisition and Domain Acquisition in February 2025 and August 2025, respectively.

We continue to implement a financial system that is designed to improve the efficiency and effectiveness of our operational and financial accounting processes.

This implementation is expected to be a multi-year project.

We expect that the implementation of this system will improve our internal control over financial reporting.

In November 2024, we completed the Visual Lease Acquisition.

During the three months ended December 31, [removed: 2024,] [added: 2025,] no [removed: director] [added: other directors] or [removed: officer of the Company] [added: officers, as defined in Rule 16a-1(f),] adopted or terminated a “Rule 10b5-1 trading arrangement” or [added: a] “non-Rule 10b5-1 trading arrangement,” [removed: as] each [removed: term is] [added: as] defined in Item 408 of Regulation S-K.

Insider Trading Arrangements Intended to Satisfy the Affirmative Defense of Rule 10b5-1(c)

During the three months ended December 31, 2025, two officers of the Company entered into trading plans intended to satisfy the affirmative defense of Rule 10b5-1(c) of the Exchange Act (each such trading plan, a "Plan"), as discussed below.

On November 14, 2025, Cynthia Cann, Chief Accounting Officer, entered into a Plan that provides for the sale of up to 3,986 CoStar Group Shares.

Ms. Cann’s plan terminates on July 31, 2026, for a duration of 259 days.

On December 4, 2025, Michael Desmarais, Chief Human Resources Officer, entered into a Plan that provides for the sale of up to 5,000 CoStar Group Shares.

Mr. Desmarais's Plan terminates on July 31, 2026, for a duration of 239 days.

Insider Trading Arrangements

[removed: In addition,] CoStar Group has adopted a [removed: separate] Code of Business Conduct and Ethics for its [removed: officers] [added: directors, officers, contractors,] and employees, including its principal executive, financial and accounting officers, or persons performing similar functions.

Copies of [removed: each of these codes] [added: the Code] may be found in the “Investors” section of the Company’s website at [removed: https://investors.costargroup.com/leadership.][added: https://investors.costargroup.com/corporate-governance/governance-documents.]

We have adopted an Insider Trading Compliance Policy that governs the purchase, sale, and/or other dispositions of our securities by directors, [removed: officers] [added: officers,] and employees that is reasonably designed to promote compliance with insider trading laws, [removed: rules and regulations] [added: rules, regulations,] and NYSE listing standards.

A copy of our Insider Trading Compliance Policy is [removed: filed] [added: included] as Exhibit 19.1 to this Report.

The remaining information required by this Item is incorporated by reference to our Proxy Statement for our [removed: 2025] [added: 2026] annual meeting of stockholders under the captions “Director Nominees,” “Executive Officers,” Corporate Governance Highlights,” “Board Committees,” “Insider trading arrangements and policies,” and, if applicable, “Delinquent Section 16(a) Reports.”

CoStar Group has adopted a Code of Conduct for its directors.

The information required by this Item is incorporated by reference to our Proxy Statement for our [removed: 2025] [added: 2026] annual meeting of stockholders under the captions “Compensation Discussion and Analysis,” “Director Compensation,” “Compensation Committee Interlocks and Insider Participation,” and “Compensation Committee Report.”

The information required by this Item is incorporated by reference to our Proxy Statement for our [removed: 2025] [added: 2026] annual meeting of stockholders under the captions “Equity Compensation Plan Information” and “Stock Ownership Information.”

The information required by this Item is incorporated by reference to our Proxy Statement for our [removed: 2025] [added: 2026] annual meeting of stockholders under the captions “Certain Relationships and Related Transactions” and “Corporate Governance Matters.”

The information required by this Item is incorporated by reference to our Proxy Statement for our [removed: 2025] [added: 2026] annual meeting of stockholders under the caption “Ratification of the Appointment of Independent Registered Public Accounting Firm.”

| [removed: #[2.1](https://www.sec.gov/Archives/edgar/data/1057352/000119312524103937/d828310dex21.htm)] [added: #[2.1](https://www.sec.gov/Archives/edgar/data/1057352/000119312524103937/d828310dex21.htm)] | | | | | | Agreement and Plan of Merger and Reorganization dated April 21, 2024, by and among CoStar Group, Inc., Matterport, Inc., Matrix Merger Sub, Inc. and Matrix Merger Sub II LLC (Incorporated by reference to Exhibit 2.1 to the Registrant’s Current Report on Form 8-K filed with the SEC on April 22, 2024). | | |

| [removed: *[10.1](https://www.sec.gov/Archives/edgar/data/1057352/000105735216000138/ex44-2016stockincentivepla.htm)] [added: *[10.6](https://www.sec.gov/Archives/edgar/data/1057352/000105735216000138/ex44-2016stockincentivepla.htm)] | | | | | | CoStar Group, Inc. 2016 Stock Incentive Plan (Incorporated by reference to Exhibit 4.4 to the Registration Statement on Form S-8 of the Registrant (Reg. No. 333-212278) filed with the SEC on June 28, 2016). | | |

| [removed: *[10.2](https://www.sec.gov/Archives/edgar/data/1057352/000105735218000066/csgp-3312018xex101.htm)] [added: *[10.7](https://www.sec.gov/Archives/edgar/data/1057352/000105735218000066/csgp-3312018xex101.htm)] | | | | | | First Amendment to the CoStar Group, Inc. 2016 Stock Incentive Plan (Incorporated by reference to Exhibit 10.1 to the Registrant’s Quarterly Report on Form 10-Q filed [added: with the SEC on] April 25, 2018). | | |

| [removed: *[10.3](https://www.sec.gov/Archives/edgar/data/1057352/000105735212000101/ex101.htm)] [added: [*10.25](https://www.sec.gov/Archives/edgar/data/1057352/000105735226000008/a20260213amendedexecutiv.htm)] | | | | | | CoStar Group, Inc. [removed: 2007 Stock Incentive] [added: Amended Executive Severance] Plan, [added: dated] as [removed: amended] [added: of February 13, 2026] (Incorporated by reference to Exhibit 10.1 to the [removed: Registrant’s] [added: Registrant's] Current Report on Form 8-K filed [removed: June 8, 2012).] [added: with the SEC on February 13, 2026).] | | |

| [removed: *[10.4](https://www.sec.gov/Archives/edgar/data/1057352/000105735208000004/frenchsub_plan.htm)] [added: *[10.15](https://www.sec.gov/Archives/edgar/data/1057352/000105735216000143/csgp-6302016xex102.htm)] | | | | | | CoStar Group, Inc. [removed: 2007 Stock] [added: 2016 Cash] Incentive Plan [removed: French Sub-Plan] (Incorporated by reference to Exhibit [removed: 10.3] [added: 10.2] to the Registrant’s [added: Quarterly] Report on Form [removed: 10-K] [added: 10-Q] filed [removed: February 29, 2008).] [added: with the SEC on July 28, 2016).] | | |

| [removed: *[10.5](https://www.sec.gov/Archives/edgar/data/1057352/000105735216000143/csgp-6302016xex103.htm)] [added: *[10.8](https://www.sec.gov/Archives/edgar/data/1057352/000105735216000143/csgp-6302016xex103.htm)] | | | | | | Form of CoStar Group, Inc. 2016 Plan Restricted Stock Grant Agreement between the Registrant and certain of its officers, directors and employees (Incorporated by reference to Exhibit 10.3 to the Registrant’s Quarterly Report on Form 10-Q filed [added: with the SEC on] July 28, 2016). | | |

| [removed: *[10.6](https://www.sec.gov/Archives/edgar/data/1057352/000105735216000143/csgp-6302016xex104.htm)] [added: *[10.9](https://www.sec.gov/Archives/edgar/data/1057352/000105735216000143/csgp-6302016xex104.htm)] | | | | | | Form of CoStar Group, Inc. 2016 Plan Restricted Stock Grant Agreement for Service Awards between the Registrant and certain of its officers and employees (Incorporated by reference to Exhibit 10.4 to the Registrant’s Quarterly Report on Form 10-Q filed [added: with the SEC on] July 28, 2016). | | |

| [removed: *[10.7](https://www.sec.gov/Archives/edgar/data/1057352/000105735216000143/csgp-6302016xex105.htm)] [added: *[10.10](https://www.sec.gov/Archives/edgar/data/1057352/000105735216000143/csgp-6302016xex105.htm)] | | | | | | Form of CoStar Group, Inc. 2016 Plan Restricted Stock Unit Grant Agreement between the Registrant and certain of its officers and employees (Incorporated by reference to Exhibit 10.5 to the Registrant’s Quarterly Report on Form 10-Q filed [added: with the SEC on] July 28, 2016). | | |

| [removed: *[10.8](https://www.sec.gov/Archives/edgar/data/1057352/000105735216000143/csgp-6302016xex106.htm)] [added: *[10.11](https://www.sec.gov/Archives/edgar/data/1057352/000105735216000143/csgp-6302016xex106.htm)] | | | | | | Form of CoStar Group, Inc. 2016 Plan Incentive Stock Option Grant Agreement between the Registrant and certain of its officers and employees (Incorporated by reference to Exhibit 10.6 to the Registrant’s Quarterly Report on Form 10-Q filed [added: with the SEC on] July 28, 2016). | | |

| [removed: *[10.9](https://www.sec.gov/Archives/edgar/data/1057352/000105735216000143/csgp-6302016xex107.htm)] [added: *[10.12](https://www.sec.gov/Archives/edgar/data/1057352/000105735216000143/csgp-6302016xex107.htm)] | | | | | | Form of CoStar Group, Inc. 2016 Plan Incentive Stock Option Grant Agreement between the Registrant and Andrew C. Florance (Incorporated by reference to Exhibit 10.7 to the Registrant’s Quarterly Report on Form 10-Q filed [added: with the SEC on] July 28, 2016). | | |

| [removed: *[10.10](https://www.sec.gov/Archives/edgar/data/1057352/000105735216000143/csgp-6302016xex108.htm)] [added: *[10.13](https://www.sec.gov/Archives/edgar/data/1057352/000105735216000143/csgp-6302016xex108.htm)] | | | | | | Form of CoStar Group, Inc. 2016 Plan Nonqualified Stock Option Grant Agreement between the Registrant and certain of its officers, directors and employees (Incorporated by reference to Exhibit 10.8 to the Registrant’s Quarterly Report on Form 10-Q filed [added: with the SEC on] July 28, 2016). | | |

| [removed: *[10.11](https://www.sec.gov/Archives/edgar/data/1057352/000105735216000143/csgp-6302016xex109.htm)] [added: *[10.14](https://www.sec.gov/Archives/edgar/data/1057352/000105735216000143/csgp-6302016xex109.htm)] | | | | | | Form of CoStar Group, Inc. 2016 Plan Nonqualified Stock Option Grant Agreement between the Registrant and Andrew C. Florance (Incorporated by reference to Exhibit 10.9 to the Registrant’s Quarterly Report on Form 10-Q filed [added: with the SEC on] July 28, 2016). | | |

| [removed: *[10.12](https://www.sec.gov/Archives/edgar/data/1057352/000105735207000051/ex_99-1.htm)] [added: [*10.2](https://www.sec.gov/Archives/edgar/data/1057352/000105735225000120/ex102costar-formrsagrant.htm)] | | | | | | Form of [removed: 2007] [added: CoStar Group, Inc. 2025 Stock Incentive] Plan Restricted Stock Grant Agreement between the Registrant and certain of its officers, directors and employees (Incorporated by reference to Exhibit [removed: 99.1] [added: 10.2] to the Registrant’s [removed: Current] [added: Quarterly] Report on Form [removed: 8-K] [added: 10-Q] filed [removed: June 22, 2007).] [added: with the SEC on October 29, 2025).] | | |

| [removed: *[10.13](https://www.sec.gov/Archives/edgar/data/1057352/000105735214000006/csgp-ex108_20131231.htm)] [added: [*10.3](https://www.sec.gov/Archives/edgar/data/1057352/000105735225000120/ex103costar-formrsugrant.htm)] | | | | | | Form of [removed: 2007] [added: CoStar Group, Inc. 2025 Stock Incentive] Plan Restricted Stock Unit [added: Grant] Agreement between the Registrant and certain of its [removed: officers] [added: officers, directors] and employees (Incorporated by reference to Exhibit [removed: 10.8] [added: 10.3] to the [removed: Registrant's Annual] [added: Registrant’s Quarterly] Report on Form [removed: 10-K] [added: 10-Q] filed [removed: February 20, 2014).] [added: with the SEC on October 29, 2025).] | | |

| [removed: *[10.14](https://www.sec.gov/Archives/edgar/data/1057352/000105735209000013/iso2007agrmt.htm)] [added: [*10.4](https://www.sec.gov/Archives/edgar/data/1057352/000105735225000120/ex104costar-formrsgranta.htm)] | | | | | | Form of [removed: 2007 Plan] [added: CoStar Group, Inc. 2025 Stock] Incentive [added: Plan Restricted] Stock [removed: Option] Grant Agreement [added: for Service Awards] between the Registrant and certain of its [removed: officers] [added: officers, directors] and employees (Incorporated by reference to Exhibit [removed: 10.8] [added: 10.4] to the Registrant’s [removed: Annual] [added: Quarterly] Report on Form [removed: 10-K] [added: 10-Q] filed [removed: February 24, 2009).] [added: with the SEC on October 29, 2025).] | | |

| [removed: *[10.15](https://www.sec.gov/Archives/edgar/data/1057352/000105735209000013/iso2007agrmt_w-florance.htm)] [added: *[10.22](https://www.sec.gov/Archives/edgar/data/1057352/000105735209000013/firstamd-florance_empagrmt.htm)] | | | | | | [removed: Form of 2007 Plan Incentive Stock Option Grant Agreement between the Registrant and] [added: First Amendment to] Andrew C. Florance [added: Employment Agreement, effective January 1, 2009] (Incorporated by reference to Exhibit [removed: 10.9] [added: 10.16] to the Registrant’s Annual Report on Form 10-K filed [added: with the SEC on] February 24, 2009). | | |

| [removed: *[10.16](https://www.sec.gov/Archives/edgar/data/1057352/000105735209000013/nqso2007agrmt.htm)] [added: [*10.5](https://www.sec.gov/Archives/edgar/data/1057352/000105735226000020/ex1052025formofpsuagreem.htm)] | | | | | | Form of [removed: 2007] [added: CoStar Group Inc. 2025 Stock Incentive] Plan [removed: Nonqualified] [added: Performance] Stock [removed: Option] [added: Unit] Grant Agreement between the Registrant and certain of its officers [removed: and employees (Incorporated by reference to Exhibit 10.10 to the Registrant’s Annual Report on Form 10-K filed February 24, 2009).] [added: (filed herewith).] | | |

| [removed: *[10.17](https://www.sec.gov/Archives/edgar/data/1057352/000105735209000013/nqso2007agrmt_w-dir.htm)] [added: [10.24](https://www.sec.gov/Archives/edgar/data/1057352/000095013304001856/w96989exv10w1.htm)] | | | | | | Form of [removed: 2007 Plan Nonqualified Stock Option Grant] [added: Indemnification] Agreement between the Registrant and [removed: certain] [added: each] of its [added: officers and] directors (Incorporated by reference to Exhibit [removed: 10.11] [added: 10.1] to the Registrant’s [removed: Annual] [added: Quarterly] Report on Form [removed: 10-K] [added: 10-Q] filed [removed: February 24, 2009).] [added: with the SEC on May 7, 2004).] | | |

| [removed: *[10.20](https://www.sec.gov/Archives/edgar/data/1057352/000105735216000143/csgp-6302016xex102.htm)] [added: [19.1](https://www.sec.gov/Archives/edgar/data/1057352/000105735225000016/csgp-ex19120241231.htm)] | | | | | | CoStar Group, Inc. [removed: 2016 Cash Incentive Plan] [added: Insider Trading Compliance Policy] (Incorporated by reference to Exhibit [removed: 10.2] [added: 19.1] to the [removed: Registrant’s Quarterly] [added: Registrant's Annual] Report on Form [removed: 10-Q] [added: 10-K] filed [removed: July 28, 2016).] [added: with the SEC on February 20, 2025).] | | |

| [removed: *[10.21](https://www.sec.gov/Archives/edgar/data/1057352/000105735221000080/secondaresppplanasapproved.htm)] [added: *[10.17](https://www.sec.gov/Archives/edgar/data/1057352/000105735221000080/secondaresppplanasapproved.htm)] | | | | | | Second Amended and Restated Employee Stock Purchase Plan (Incorporated by reference to Exhibit 4.4 to the Registrant’s Registration Statement on Form S-8 ( Reg. No. 333-258220) filed with the SEC on July 28, 2021). | | |

| [removed: *[10.22](https://www.sec.gov/Archives/edgar/data/1057352/000105735225000016/csgp-ex102220241231.htm)] [added: *[10.18](https://www.sec.gov/Archives/edgar/data/1057352/000105735225000016/csgp-ex102220241231.htm)] | | | | | | Canadian Addendum to CoStar Group ESPP [removed: (filed herewith).] [added: (Incorporated by reference to Exhibit 10.22 to the Registrant's Annual Report on Form 10-K filed with the SEC on February 20, 2025).] | | |

| [removed: *[10.23](https://www.sec.gov/Archives/edgar/data/1057352/000105735218000011/csgp-ex1021_20171207.htm)] [added: [*10.19](https://www.sec.gov/Archives/edgar/data/1057352/000105735226000020/csgp-ex101920251231.htm)] | | | | | | CoStar Group, Inc. [added: Amended and Restated CoStar Group, Inc.] Management Stock Purchase Plan [removed: (Incorporated by reference to Exhibit 10.21 to the Registrant’s Annual Report on Form 10-K filed February 23, 2018).] [added: (filed herewith).] | | |

| [removed: *[10.24](https://www.sec.gov/Archives/edgar/data/1057352/000105735213000078/csgp-9302013xex101.htm)] [added: *[10.20](https://www.sec.gov/Archives/edgar/data/1057352/000105735226000020/csgp-ex102020251231.htm)] | | | | | | Summary of Non-Employee Director Compensation [removed: (Incorporated by reference to Exhibit 10.1 to the Registrant's Quarterly Report on Form 10-Q filed on October 24, 2013).] [added: (filed herewith).] | | |

| [removed: *[10.25](https://www.sec.gov/Archives/edgar/data/1057352/0001005150-98-000402.txt)] [added: *[10.21](https://www.sec.gov/Archives/edgar/data/1057352/0001005150-98-000402.txt)] | | | | | | Employment Agreement for Andrew C. Florance (Incorporated by reference to Exhibit 10.2 to Amendment No. 1 to the Registrant's Registration Statement on Form S-1 (Reg. No. 333-47953) filed with the SEC on April 27, 1998). | | |

| [removed: *[10.26](https://www.sec.gov/Archives/edgar/data/1057352/000105735209000013/firstamd-florance_empagrmt.htm)] [added: [*10.23](https://www.sec.gov/Archives/edgar/data/1057352/000105735226000004/a20260106secondamendment.htm)] | | | | | | [removed: First] [added: Second] Amendment to Andrew C. Florance Employment Agreement, [removed: effective] [added: entered into] January [removed: 1, 2009] [added: 6, 2026] (Incorporated by reference to Exhibit [removed: 10.16] [added: 10.1] to the [removed: Registrant’s Annual] [added: Registrant's Current] Report on Form [removed: 10-K] [added: 8-K] filed [removed: February 24, 2009).] [added: with the SEC on January 7, 2026).] | | |

| [removed: [10.28](https://www.sec.gov/Archives/edgar/data/1057352/000105735211000072/lease.htm)] [added: [10.26](https://www.sec.gov/Archives/edgar/data/1057352/000105735211000072/lease.htm)] | | | | | | Deed of Office Lease by and between GLL L-Street 1331, LLC and CoStar Realty Information, Inc., dated February 18, 2011, and made effective as of June 1, 2010 (Incorporated by reference to Exhibit 10.1 to the Registrant’s Quarterly Report on form 10-Q filed [added: with the SEC] on April 29, 2011). | | |

| [removed: #[10.29](https://www.sec.gov/Archives/edgar/data/1057352/000119312524151700/d794196dex101.htm)] [added: [10.27](https://www.sec.gov/Archives/edgar/data/1057352/000119312524151700/d794196dex101.htm)] | | | | | | Credit Agreement, dated as of May 24, 2024, by and among CoStar Group, Inc., as borrower, the lenders party thereto and Bank of America, N.A., as administrative agent (Incorporated by reference to Exhibit 10.1 to the Registrant’s Current Report on Form 8-K filed with the SEC on May 31, 2024). | | |

| [removed: [19.1](https://www.sec.gov/Archives/edgar/data/1057352/000105735225000016/csgp-ex19120241231.htm)] [added: [*10.16](https://www.sec.gov/Archives/edgar/data/1057352/000105735226000020/ex1016costar-2026annualc.htm)] | | | | | | CoStar [removed: Group,] [added: Group] Inc. [removed: Insider Trading Compliance Policy] [added: 2026 Cash Incentive Plan] (filed herewith). | | |

| [removed: [21.1](https://www.sec.gov/Archives/edgar/data/1057352/000105735225000016/csgp-ex21120241231.htm)] [added: [21.1](https://www.sec.gov/Archives/edgar/data/1057352/000105735226000020/csgp-ex21120251231.htm)] | | | | | | Subsidiaries of the Registrant (filed herewith). | | |

| [removed: [23.1](https://www.sec.gov/Archives/edgar/data/1057352/000105735225000016/csgp-ex23120241231.htm)] [added: [23.1](https://www.sec.gov/Archives/edgar/data/1057352/000105735226000020/csgp-ex23120251231.htm)] | | | | | | Consent of Ernst & Young LLP, Independent Registered Public Accounting Firm (filed herewith). | | |

| [removed: [31.1](https://www.sec.gov/Archives/edgar/data/1057352/000105735225000016/csgp-ex31120241231.htm)] [added: [31.1](https://www.sec.gov/Archives/edgar/data/1057352/000105735226000020/csgp-ex31120251231.htm)] | | | | | | Certification of Principal Executive Officer pursuant to Section 302 of the Sarbanes-Oxley Act of 2002 (filed herewith). | | |

| [removed: [31.2](https://www.sec.gov/Archives/edgar/data/1057352/000105735225000016/csgp-ex31220241231.htm)] [added: [31.2](https://www.sec.gov/Archives/edgar/data/1057352/000105735226000020/csgp-ex31220251231.htm)] | | | | | | Certification of Principal Financial Officer pursuant to Section 302 of the Sarbanes-Oxley Act of 2002 (filed herewith). | | |

| [removed: [32.1](https://www.sec.gov/Archives/edgar/data/1057352/000105735225000016/csgp-ex32120241231.htm)] [added: [32.1](https://www.sec.gov/Archives/edgar/data/1057352/000105735226000020/csgp-ex32120251231.htm)] | | | | | | Certification of Principal Executive Officer pursuant to 18 U.S.C. Sec. 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002 (furnished herewith). | | |

| [removed: [32.2](https://www.sec.gov/Archives/edgar/data/1057352/000105735225000016/csgp-ex32220241231.htm)] [added: [32.2](https://www.sec.gov/Archives/edgar/data/1057352/000105735226000020/csgp-ex32220251231.htm)] | | | | | | Certification of Principal Financial Officer pursuant to 18 U.S.C. Sec. 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002 (furnished herewith). | | |

| 101.INS | | | | | | The following financial statements from the Company’s Annual Report on Form 10-K for the year ended December 31, [removed: 2024,] [added: 2025,] formatted in Inline XBRL: (i) Consolidated Statements of Operations; (ii) Consolidated Statements of Comprehensive Income; (iii) Consolidated Balance Sheets; (iv) Consolidated Statements of Cash Flows; and (v) Notes to Consolidated Financial Statements, tagged as blocks of text and including detailed tags. | | |

| 104 | | | | | | The cover page from the Registrant's Annual Report on Form 10-K for the year ended December 31, [removed: 2024,] [added: 2025,] formatted in Inline XBRL (included as Exhibit 101). | | |

| [*10.1](https://www.sec.gov/Archives/edgar/data/1057352/000119312525107493/d821281ddef14a.htm#toc821281_48) | | | | | | CoStar Group, Inc. 2025 Stock Incentive Plan (Incorporated by reference to Appendix B to Registrant’s Definitive Proxy Statement on Schedule 14A filed with the SEC on April 30, 2025). | | |

| [10.28](https://www.sec.gov/Archives/edgar/data/1057352/000119312525074119/d937923dex101.htm) | | | | | | Support Agreement, dated as of April 6, 2025, among the Company, D. E. Shaw & Co., L.P. and D. E. Shaw Oculus Portfolios, L.L.C (Incorporated by reference to Exhibit 10.1 to the Registrant’s Current Report on Form 8-K filed with the SEC on April 7, 2025). | | |

| [10.29](https://www.sec.gov/Archives/edgar/data/1057352/000119312525074119/d937923dex102.htm) | | | | | | Support Agreement, dated as of April 6, 2025, among the Company and Third Point parties thereto (Incorporated by reference to Exhibit 10.2 to the Registrant’s Current Report on Form 8-K filed with the SEC on April 7, 2025). | | |

| [*10.30](https://www.sec.gov/Archives/edgar/data/1057352/000119312525042496/d933213dex991.htm) | | | | | | Matterport, Inc. 2021 Incentive Award Plan (Incorporated by reference to Exhibit 99.1 to the Registrant’s Registration Statement on Form S-8 (File No. 333-285422) filed with the SEC on February 28, 2025) | | |

| [*10.31](https://www.sec.gov/Archives/edgar/data/1057352/000119312525042496/d933213dex992.htm) | | | | | | Form of Option Agreement under the Matterport, Inc. 2021 Incentive Award Plan (Incorporated by reference to Exhibit 99.2 to the Registrant’s Registration Statement on Form S-8 (File No. 333-285422) filed with the SEC on February 28, 2025). | | |

| [*10.32](https://www.sec.gov/Archives/edgar/data/1057352/000119312525042496/d933213dex993.htm) | | | | | | Form of Restricted Stock Unit Agreement under the Matterport, Inc. 2021 Incentive Award Plan (Incorporated by reference to Exhibit 99.3 to the Registrant’s Registration Statement on Form S-8 (File No. 333-285422) filed with the SEC on February 28, 2025). | | |

| [*10.33](https://www.sec.gov/Archives/edgar/data/1057352/000119312525042496/d933213dex994.htm) | | | | | | Matterport, Inc. Amended and Restated 2011 Stock Incentive Plan (Incorporated by reference to Exhibit 99.4 to the Registrant’s Registration Statement on Form S-8 (File No. 333-285422) filed with the SEC on February 28, 2025). | | |

| [*10.34](https://www.sec.gov/Archives/edgar/data/1057352/000119312525042496/d933213dex995.htm) | | | | | | Form of Option Agreement under the Matterport, Inc. Amended and Restated 2011 Stock Incentive Plan (Incorporated by reference to Exhibit 99.5 to the Registrant’s Registration Statement on Form S-8 (File No. 333-285422) filed with the SEC on February 28, 2025). | | |

| [*10.35](https://www.sec.gov/Archives/edgar/data/1057352/000119312525042496/d933213dex996.htm) | | | | | | Form of Restricted Stock Unit Agreement under the Matterport, Inc. Amended and Restated 2011 Stock Incentive Plan (Incorporated by reference to Exhibit 99.6 to the Registrant’s Registration Statement on Form S-8 (File No. 333-285422) filed with the SEC on February 28, 2025). | | |

| [10.36](https://www.sec.gov/Archives/edgar/data/1057352/000105735225000069/schemeimplementationdeed.htm) | | | | | | Scheme Implementation Deed, dated May 9, 2025, by and between CoStar Group, Inc., Domain Holdings Australia Limited and Andromeda Australia SubCo Pty Limited (Incorporated by reference to Exhibit 10.1 to the Registrant’s Current Report on Form 8-K filed with the SEC on May 9, 2025). | | |

| *[10.18](https://www.sec.gov/Archives/edgar/data/1057352/000105735209000013/nqso2007agrmt_w-florance.htm) | | | | | | Form of 2007 Plan Nonqualified Stock Option Grant Agreement between the Registrant and Andrew C. Florance (Incorporated by reference to Exhibit 10.12 to the Registrant’s Annual Report on Form 10-K filed February 24, 2009). | | |

| *[10.19](https://www.sec.gov/Archives/edgar/data/1057352/000105735208000004/rest_stockform-frenchsubform.htm) | | | | | | Form of 2007 Plan French Sub-Plan Restricted Stock Agreement between the Registrant and certain of its employees (Incorporated by reference to Exhibit 10.10 to the Registrant’s Annual Report on Form 10-K filed February 29, 2008). | | |

| [10.27](https://www.sec.gov/Archives/edgar/data/1057352/000095013304001856/w96989exv10w1.htm) | | | | | | Form of Indemnification Agreement between the Registrant and each of its officers and directors (Incorporated by reference to Exhibit 10.1 to the Registrant’s Quarterly Report on Form 10-Q filed on May 7, 2004). | | |

| February [removed: 19, 2025] [added: 25, 2026] | | | | | | Andrew C. Florance | | |

| /s/ Andrew C. Florance | | | | | | Chief Executive Officer and | | | | | | February [removed: 19, 2025] [added: 25, 2026] | | |

| /s/ Christian M. Lown | | | | | | Chief Financial Officer | | | | | | February [removed: 19, 2025] [added: 25, 2026] | | |

| /s/ Cynthia C. Cann | | | | | | Chief Accounting Officer | | | | | | February [removed: 19, 2025] [added: 25, 2026] | | |

| /s/ Angelique G. Brunner | | | | | | Director | | | | | | February [removed: 19, 2025] [added: 25, 2026] | | |

| /s/ John W. Hill | | | | | | Director | | | | | | February [removed: 19, 2025] [added: 25, 2026] | | |

| /s/ Robert W. Musslewhite | | | | | | Director | | | | | | February [removed: 19, 2025] [added: 25, 2026] | | |

| Reports of Independent Registered Public Accounting Firm (PCAOB ID Number 42) | | | [removed: [F-](#i41275714db3541c8a24982c2435763d8_136)[2](#i41275714db3541c8a24982c2435763d8_136)] [added: [F-](#ib08faba301d94dee895ca69fb9a28832_133)[2](#ib08faba301d94dee895ca69fb9a28832_133)] | | |

| Consolidated Statements of Operations | | | [removed: [F-](#i41275714db3541c8a24982c2435763d8_139)[6](#i41275714db3541c8a24982c2435763d8_139)] [added: [F-](#ib08faba301d94dee895ca69fb9a28832_136)[7](#ib08faba301d94dee895ca69fb9a28832_136)] | | |

| Consolidated Statements of Comprehensive Income | | | [removed: [F-](#i41275714db3541c8a24982c2435763d8_142)[7](#i41275714db3541c8a24982c2435763d8_142)] [added: [F-](#ib08faba301d94dee895ca69fb9a28832_139)[8](#ib08faba301d94dee895ca69fb9a28832_139)] | | |

| Consolidated Balance Sheets | | | [removed: [F-](#i41275714db3541c8a24982c2435763d8_145)[8](#i41275714db3541c8a24982c2435763d8_145)] [added: [F-](#ib08faba301d94dee895ca69fb9a28832_142)[9](#ib08faba301d94dee895ca69fb9a28832_142)] | | |

| Consolidated Statements of Changes in Stockholders’ Equity | | | [removed: [F-](#i41275714db3541c8a24982c2435763d8_148)[9](#i41275714db3541c8a24982c2435763d8_148)] [added: [F-](#ib08faba301d94dee895ca69fb9a28832_145)[10](#ib08faba301d94dee895ca69fb9a28832_145)] | | |

| Consolidated Statements of Cash Flows | | | [removed: [F-](#i41275714db3541c8a24982c2435763d8_151)[10](#i41275714db3541c8a24982c2435763d8_151)] [added: [F-](#ib08faba301d94dee895ca69fb9a28832_148)[11](#ib08faba301d94dee895ca69fb9a28832_148)] | | |

[removed: | Notes to Consolidated Financial Statements | | | [F-](#i41275714db3541c8a24982c2435763d8_154)[12](#i41275714db3541c8a24982c2435763d8_154) | | |][added: NOTES TO CONSOLIDATED FINANCIAL STATEMENTS]

To the Stockholders and [added: the] Board of Directors of CoStar Group, Inc.

We have audited the accompanying consolidated balance sheets of CoStar Group, Inc. (the Company) as of December 31, [removed: 2024] [added: 2025] and [removed: 2023,] [added: 2024,] the related consolidated statements of operations, comprehensive income, changes in stockholders’ equity and cash flows for each of the three years in the period ended December 31, [removed: 2024,] [added: 2025,] and the related notes (collectively referred to as the “consolidated financial statements”).

In our opinion, the consolidated financial statements present fairly, in all material respects, the financial position of the Company at December 31, [removed: 2024] [added: 2025] and [removed: 2023,] [added: 2024,] and the results of its operations and its cash flows for each of the three years in the period ended December 31, [removed: 2024,] [added: 2025,] in conformity with U.S. generally accepted accounting principles.

We also have audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States) (PCAOB), the Company's internal control over financial reporting as of December 31, [removed: 2024,] [added: 2025,] based on criteria established in Internal Control-Integrated Framework issued by the Committee of Sponsoring Organizations of the Treadway Commission (2013 framework), and our report dated February [removed: 19, 2025] [added: 25, 2026] expressed an unqualified opinion thereon.

Critical Audit [removed: Matter][added: Matters]

The critical audit [removed: matter] [added: matters] communicated below [removed: is a matter] [added: are matters] arising from the current period audit of the financial statements that [removed: was] [added: were] communicated or required to be communicated to the audit committee and that: (1) [removed: relates] [added: relate] to accounts or disclosures that are material to the financial statements and (2) involved our especially challenging, subjective or complex judgments.

The communication of [removed: the] critical audit [removed: matter] [added: matters] does not alter in any way our opinion on the consolidated financial statements, taken as a whole, and we are not, by communicating the critical audit [removed: matter] [added: matters] below, providing [removed: a] separate [removed: opinion] [added: opinions] on the critical audit [removed: matter] [added: matters] or on the accounts or disclosures to which [removed: it relates.][added: they relate.]