Item 1A. Risk Factors

In addition to the other information set forth in this Report, you should carefully consider the factors disclosed in Part I, Item 1A, “Risk Factors” in our 2025 Form 10-K, which could materially affect our business, financial condition or future results. Additional risks and uncertainties not currently known to us, or that we currently deem to be immaterial, may also have a material adverse effect on our business, financial condition, and/or results of operations. Other than the following items, there have not been any material changes to the risk factors as previously disclosed in Part I, Item 1A, "Risk Factors” in our 2025 Form 10-K.

Risks related to our business

We may be unable to complete the acquisition of Zonda or otherwise realize the benefits of the pending Zonda acquisition, which could have an adverse effect on us.

On May 28, 2026, we announced that we had entered into the Zonda Agreement, to acquire Zonda. Pursuant to the Zonda Agreement, and subject to the terms and conditions contained therein, at the closing of the Zonda Acquisition, among other things, we will acquire all of the issued and outstanding capital stock of Zonda in a cash transaction. The closing of the Zonda Acquisition is subject to certain customary closing conditions, including, among others: expiration or termination of the applicable waiting periods under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, and certain other regulatory laws; the absence of any law, order, decree, ruling or injunction of a governmental authority with jurisdiction prohibiting or making illegal the consummation of the Zonda Acquisition; the accuracy of each party’s representations and warranties and the performance and compliance by each party with its respective covenants in each case subject to certain qualifiers; there not having occurred since the date of the Zonda 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; and the delivery of customary closing documents.

Until the completion of the Zonda Acquisition, we will operate independently of Zonda. It is possible that the pendency of the Zonda Acquisition could result in the loss of key employees, higher than expected costs, diversion of management attention, or the disruption of our ongoing businesses, which may adversely affect the combined company’s ability to maintain relationships with customers, vendors, and employees or to achieve the anticipated benefits of the Zonda Acquisition.

We have incurred, and we will continue to incur, transaction fees, including legal, regulatory and other costs associated with closing the Zonda Acquisition, as well as expenses related to formulating and implementing integration plans, including systems consolidation costs and employment-related costs. We may be unable to offset transaction and integration-related costs with the realization of other efficiencies related to the integration of the business.

The success of the Zonda Acquisition, if completed, will depend in part on our ability to realize the anticipated business opportunities and growth prospects from combining our business with that of Zonda. We may never realize these business opportunities and growth prospects. Integrating operations and employees will require significant efforts and expenditures. If we are unable to successfully or timely acquire and integrate Zonda’s business with ours, we may be unable to realize the growth, synergies, and other anticipated benefits resulting from the Zonda Acquisition and our business could be adversely affected.

**Item 2.**Unregistered Sales of Equity Securities and Use of Proceeds

The following table is a summary of our repurchases of common stock during each of the three months ended June 30, 2026:

ISSUER PURCHASES OF EQUITY SECURITIES

(1) The number 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 2025 Stock Incentive Plan, for which shares were purchased by the Company based on their fair market value on the trading day immediately preceding the vesting date.

(2) In December 2025, the Board of Directors approved the Stock Repurchase Program which authorizes the repurchase of up to $1.5 billion of outstanding CoStar Group Shares, with no expiration date. During the three months ended June 30, 2026, the Company repurchased 2.4 million CoStar Group Shares for an aggregate cost of $83 million. See Note 13 for further discussion regarding the Stock Repurchase Program and stock repurchase activity.

**Item 3.**Defaults Upon Senior Securities

None.

**Item 4.**Mine Safety Disclosures

Not applicable.