Pinnacle West Capital (PNW) 10-K risk factor changes: FY2025 vs FY2024

See Note [removed: 10.][added: 14.]

The ACC must also approve APS’s issuance of equity and debt [removed: securities,] [added: securities] and any significant transfer or encumbrance of APS property used to provide retail electric service and must approve or receive prior notification of certain transactions between us, APS, and our respective affiliates, including the infusion of equity into APS.

APS must comply in good faith with all applicable statutes, regulations, rules, tariffs, [added: executive orders] and orders of agencies that regulate APS’s business, including FERC, NRC, EPA, the ACC, and state and local governmental agencies.

These [added: laws, regulations, and] agencies regulate many aspects of APS’s utility operations, including safety and performance, emissions, siting and construction of facilities, labor and employment, customer service and the rates that APS can charge retail and wholesale customers.

Concern over climate change has led to significant legislative and regulatory efforts to limit [removed: CO2,] [added: carbon dioxide,] which is a major byproduct of the combustion of fossil fuel, and other GHG emissions.

*Potential Financial Risks — [removed: Greenhouse Gas] [added: GHG] Regulation, the Clean Power Plan and Potential Litigation.* On April 25, 2024, [removed: the] EPA issued new GHG emission standards for power plants.

The new regulations are currently being challenged in federal [removed: court.][added: court and, in 2025, EPA proposed a rule to repeal these GHG emission standards.]

See [removed: Item 1 -] [added: “Business of Arizona Public Service Company —] Environmental Matters [removed: -] [added: —] Climate [removed: Change] [added: Change” in Part I, Item 1] for more information.

See Note [removed: 3] [added: 8] for a discussion of the Navajo Plant and Cholla [removed: retirement] [added: retirements] and the related risks associated with APS’s continued recovery of its remaining investment in the plant.

Deregulation or restructuring of the electric industry [added: and other factors] may result in increased competition, which could have a significant adverse impact on APS’s business and its results of operations.

Modification of the ACC’s retail electric competition rules or other efforts of deregulation [removed: could] [added: and other factors, such as customers installing behind the meter technologies or large customers developing large, utility scale generation projects to serve their energy needs, may] result [removed: in] increased competition, which could have a significant adverse impact on APS’s business and results of operations.

*Effects of Energy Conservation Measures and Distributed Energy Resources.* APS customers [added: participate] in energy efficiency and conservation programs and other [removed: demand-side management] [added: DSM] efforts, which in turn impact the demand for electricity.

The distributed renewable energy requirement is 30% of the applicable RES requirement for 2012 and subsequent years (APS [removed: requested] [added: was granted] a waiver of this requirement in [removed: the 2024 and 2025] [added: its 2026] RES Implementation [removed: Plans, which have not yet been approved by the ACC).][added: Plan).]

[added: Customer participation] in distributed renewable energy programs would result in lower demand since customers would be meeting some of their own energy needs.

*Actual and Projected Customer and Sales Growth.* [removed: APS’s actual] [added: Actual] sales growth, excluding weather-related variations, may differ from [removed: its] [added: our] projections as a result of numerous factors, such as [removed: economic] [added: macroeconomic] conditions, [removed: customer growth, the legal,] [added: current and future economic,] regulatory, [added: business,] and [removed: business environment in Arizona,] [added: other conditions, such as the Arizona housing market, customer growth,] usage patterns and energy conservation, slower [removed: than expected] ramp-up of and/or fewer [removed: than expected] [added: large] data centers and [removed: large] manufacturing facilities, slower than expected commercial and industrial expansions, impacts of energy efficiency programs and growth in DG, responses to retail price changes, changes in regulatory standards, and impacts of new and existing laws and regulations, including environmental laws and regulations.

Based on past experience, a 1% variation in our annual residential and small commercial and industrial kWh sales projections under normal business conditions can result in increases or decreases in annual net income of approximately [removed: $24] [added: $25] million, and a 1% variation in our annual large commercial and industrial kWh sales projections under normal business conditions can result in increases or decreases in annual net income of approximately [removed: $6] [added: $7] million.

[removed: APS is implementing strategies to attempt to reduce this risk; however, the difficulty in forecasting these demands and the] additional risk of these arrangements could lead to stranded costs and other effects that could have material adverse impacts on APS’s financial condition, results of operations, and cash flows.

Concerns over the physical security of these assets could include damage to certain of our [added: facilities due to vandalism or other deliberate acts that could lead to outages or other adverse effects.]

If APS’s facilities operate below expectations, especially during its peak [removed: seasons,] [added: season,] it may lose revenue or incur additional expenses, including increased purchased power expenses.

Additionally, as APS’s transmission infrastructure ages and its transmission system needs [added: to] grow to support growth in our territory and in the Southwest, it will need to replace and expand certain portions of its transmission infrastructure, which requires significant investment of capital.

Certain replacements and expansions of the transmission infrastructure will also require the acquisition or renewal of land leases, easements, or other rights-of-way that may require approvals from landowners, including individuals, [removed: governmental] [added: government] agencies, and, at times, tribal nations.

[removed: If APS is unable to successfully manage the] replacement and expansion of its transmission infrastructure, it could face increased equipment failures, power quality challenges, reputational impact, and financial loss.

The inability to successfully develop, acquire or operate generation [removed: resources] [added: and transmission facilities] to meet future resource needs and load forecasts in accordance with reliability requirements and other new or evolving standards and regulations could adversely impact our business.

[removed: The current regulatory standards, laws,] [added: Current laws] and regulations [added: as well as changes to those laws and regulations, including via judicial decisions and executive orders,] create strategic challenges [removed: as to the] [added: in acquiring an] appropriate generation portfolio and fuel diversification mix.

[removed: In addition,] APS is required by the ACC to meet certain energy resource portfolio requirements, including those related to renewables development and energy efficiency measures, in addition to specific competitive resource procurement requirements.

The development and operation of [removed: any generation facility] [added: these facilities] is [removed: also] subject to [removed: many] [added: other] risks, including those related to financing, siting, permitting, new and evolving technology, extreme weather events, workforce issues, cybersecurity attacks, supply [added: chain constraints for key equipment and critical spare parts, overreliance on or the existence of a small number of suppliers, access to fuel, and the construction of sufficient transmission capacity to support these facilities among others.]

APS needs to develop or acquire new generation [added: and other] facilities, potentially modernize existing facilities, and/or contract for additional capacity in order to meet future resource needs and load forecasts.

APS’s ability to successfully execute its clean energy [removed: commitment] [added: goal] is dependent upon a number of external factors, some of which include supportive national and state energy policies, a supportive regulatory environment, sales and customer growth, the development, deployment and advancement of clean energy technologies, adequate supply chain for generation resources, and continued access to capital markets.

Climate change is [removed: also] projected to exacerbate such [removed: drought conditions.]

[removed: In addition,] Colorado River water supplies for Arizona are subject to [removed: a Tier 1] shortage [removed: declaration, which] [added: declarations that] substantially [removed: limits] [added: limit] the quantity of water available [removed: for] [added: to] the state.

We are subject to [removed: cybersecurity risks and risks of] [added: risk related to cybersecurity, IT systems, and] unauthorized access to our systems that could adversely affect our business and financial condition.

These types of events [removed: would] [added: as well as the impacts of integrating new IT systems could] also require significant management attention and resources and could have a material adverse impact on our financial condition, results of operations, or cash flows.

One of these agencies, NERC, has issued comprehensive regulations and standards surrounding the security of bulk power systems and is continually in the process of developing updated and additional requirements [removed: with which the utility industry must comply.]

In addition, APS is subject to retrospective premium adjustments under its nuclear property insurance policies with [removed: Nuclear Electric Insurance Limited (“NEIL”)] [added: NEIL] for approximately [removed: $23.1] [added: $24.2] million if NEIL’s losses in any policy year exceed accumulated funds and if the retrospective premium assessment is declared by NEIL’s Board of Directors.

[added: Widespread installation and] acceptance of new technologies could also enable the entry of new market participants, such as technology companies, into the interface between APS and its customers and could have other unpredictable effects on APS’s traditional business model.

Like many companies in the electric utility industry, our workforce is maturing, with approximately [removed: 27.4%] [added: 26.1%] of employees eligible to retire by the end of [removed: 2029.][added: 2030.]

Our current ratings are set forth in “Liquidity and Capital Resources — Credit Ratings” in [added: Part II,] Item 7.

Investment performance, changing interest rates, new rules or regulations and other economic, social, and political factors could decrease the value of our benefit plan assets, nuclear decommissioning trust funds and other special use funds or increase the valuation of our related obligations, resulting in significant additional funding [removed: requirements.][added: requirements.]

Additionally, the valuation of liabilities related to our pension plan and other postretirement benefit plans are impacted by a discount rate, which is the interest rate used to discount future pension and other postretirement [added: benefit obligations.]

In addition, an ACC financing order requires APS to maintain a common equity ratio of at least 40% and does not allow APS to pay common dividends if the payment would reduce [removed: its common equity below that threshold.]

See “Business of Arizona Public Service Company — Environmental Matters” in Part I, Item 1 as well as Note 14 for examples of environmental laws and regulations and matters that could affect APS’s financial condition, results of operations and cash flows.

Recent industry trends and projections of load growth reflect significant demand from data centers to support AI as well as onshoring of manufacturing, such as advanced semiconductor manufacturing.

These data centers and large manufacturers may locate their operations within service territories other than our own.

If they do choose to locate within our service territory, we may not be able to provide sufficient electric service within the time period they require due to capital or other constraints.

APS may need to accelerate development plans of the related generation and transmission facilities to serve these potential customers, which may necessitate alternative financing structures, such as the novel subscription model we are pursuing in an effort to ensure growth pays for growth and reduce cross-subsidization of customer classes, as well as ACC approval.

APS may not be able to secure facilities or regulatory approval to support these customers in a timely manner.

Additionally, the future demand from these customers may not be realized to the extent currently projected and significant uncertainties exist regarding the future energy demand associated with data centers and AI.

The difficulty in forecasting these demands and the

If APS is unable to successfully manage the

Operating, maintaining, and developing our generation and other assets requires significant capital expenditures and operations and maintenance costs that may be difficult to maintain at adequate levels while maintaining reliability.

Macroeconomic and geopolitical factors may also impact our ability to procure the generation and other equipment we need to meet customer demand.

In August 2025, APS announced an update to its clean energy goal from zero-carbon to carbon-neutral by 2050.

drought conditions.

Due to stressed surface water and groundwater supplies, there is focus on the increased use of treated effluent to supplement statewide water supplies, which could increase competition for the treated effluent that some APS generating plants rely on.

In addition to the involvement of third parties and the associated security risks, we also face risks when integrating new IT systems, such as those associated with costs, operational efficiency, and security compliance.

Our IT systems introduce layers of execution complexity and resource risks across the entire organization.

with which the utility industry must comply.

its common equity below that threshold.

Despite the fact that the majority of APS’s trading counterparties are rated as investment grade by the rating

The Company is currently evaluating the impact of the recent U.S. Supreme Court’s decision regarding the validity of certain tariffs previously imposed under the International Emergency Powers Act, including whether any or all of the tariffs will be eligible for a refund as well as the potential for replacement tariffs under separate statutory authorities.

*Environmental Clean Up.* APS has been named as a PRP for Superfund sites in Phoenix, Arizona, and it could be named a PRP in the future for other environmental clean-up at sites identified by a regulatory body.

APS cannot predict with certainty the amount and timing of all future expenditures related to environmental matters because of the difficulty of estimating clean-up costs.

There is also uncertainty in quantifying liabilities under environmental laws that impose joint and several liability on all PRPs.

*Coal Ash.* In December 2014, the EPA issued final regulations governing the handling and disposal of CCR, which are generated as a result of burning coal and consist of, among other things, fly ash and bottom ash.

The rule regulates CCR as a non-hazardous waste.

APS disposes of CCR in ash ponds and dry storage areas.

To the extent the rule requires the closure or modification of these CCR units, modification or changes to the manner of closure of such units, or the construction of new CCR units beyond what we currently anticipate, APS would incur significant additional costs for CCR disposal.

In addition, the rule may also require corrective action to address releases from CCR disposal units or the presence of CCR constituents within groundwater near CCR disposal units above certain regulatory thresholds.

*Ozone National Ambient Air Quality Standards.* In 2015, the EPA finalized revisions to the NAAQS for ozone, which set new, more stringent standards on emissions of nitrogen oxide, a precursor to ozone, in an effort to protect human health and human welfare.

Depending on the final attainment designations for the new standards and the state implementation requirements, APS may be required to invest in new pollution control technologies and to generate emission offsets for new projects or facility expansions located in ozone nonattainment areas.

In addition, the EPA may in the future further increase the stringency of various NAAQS, including for ozone or other pollutants, such as particulate matter.

With regard to even more stringent NAAQS requirements, additional control measures and compliance costs may become necessary for APS as well as its current and potential future customers.

In November 2018, the ACC voted to re-examine the facilitation of a deregulated retail electric market in Arizona.

On July 1 and July 2, 2019, ACC Staff issued a report and initial proposed draft rules regarding possible modifications to the ACC’s retail electric competition rules.

On February 10, 2020, two ACC Commissioners filed two sets of draft proposed retail electric competition rules.

On February 12,

2020, ACC Staff issued its second report regarding possible modifications to the ACC’s retail electric competition rules.

During a July 15, 2020, ACC Staff meeting, the ACC Commissioners discussed the possible development of a retail competition pilot program, but no action was taken.

The ACC continues to discuss matters related to retail electric competition, including the potential for additional buy-through programs or other pilot programs.

In April 2022, the Arizona Legislature passed, and the Governor signed, a bill that repealed the electric deregulation law that had been in place in Arizona since 1998.

On August 27, 2024, the ACC administratively closed this docket due to inactivity and obsolescence.

Customer participation

Longer term, APS has been preparing for and can serve significant load growth from residential and business customers.

On top of these existing growth trends, APS is also now receiving unprecedented incremental requests for service from extra-large commercial energy users (over 25 MW) with very high energy demands that persist virtually around-the-clock.

These incremental requests for service by extra-large energy users far exceed available generation and transmission resource capacity in the Southwest region for the foreseeable future.

APS is exploring available options for securing sufficient electric generation and transmission to meet these projections of future customer needs; however, there are difficulties in properly forecasting the demands of these extra-large customers due to factors such as the nascent nature of the industries (e.g., artificial intelligence) that these customers are supporting and the multiple variables that impact their usage ramp-up and ultimate level of demand.

As data center and other extra-large customer opportunities evolve and develop, we may also enter into arrangements with customers and potential customers that require us to invest capital and assume credit risk related to such developments and the related generation and transmission investments before we receive any potential return.

facilities due to vandalism or other deliberate acts that could lead to outages or other adverse effects.

chain constraints for critical spare parts, and the construction of sufficient transmission capacity to support these facilities among others.

In January 2020, APS announced its goal to provide 100% clean, carbon-free electricity by 2050 with an intermediate 2030 target of achieving a resource mix that is 65% clean energy, with 45% of the generation portfolio coming from renewable energy.

Widespread installation and

We are also subject to risks related to the provision of employee healthcare benefits and healthcare reform legislation.

Any inability to fully recover these costs in our utility rates would negatively impact our financial condition.

benefit obligations.

Pending or future federal or state legislative or regulatory activity or court proceedings could increase the costs of providing medical insurance for our employees and retirees.

Any potential changes and resulting cost impacts cannot be determined with certainty at this time.

Our ability to have the benefit of their cash flows, particularly in the case of any

transaction that some, or a majority, of our shareholders might believe to be in their best interests and, in that case, may prevent or discourage attempts to remove and replace incumbent directors.

This discussion provides a comparison of the [removed: 2024] [added: 2025] results with [removed: 2023] [added: 2024] results.

For the discussion of [removed: 2023] [added: 2024] compared to [removed: 2022,] [added: 2023,] see Part II.

Management’s Discussion and Analysis of Financial Condition and Results of Operations of Pinnacle West Capital Corporation’s Annual Report on Form 10-K for the year ended December 31, [removed: 2023,] [added: 2024,] which specific discussion is incorporated herein by reference.

Pinnacle West is an investor-owned electric utility holding company based in Phoenix, Arizona with consolidated assets of approximately [removed: $26] [added: $30] billion.

Since 1886, [removed: Pinnacle West] [added: APS] and [removed: our] [added: its] affiliates have provided energy and energy-related products to people and businesses throughout Arizona.

[removed: Pinnacle West derives] [added: We derive] essentially all of our revenues and earnings from our principal subsidiary, APS.

APS is Arizona’s largest and longest-serving electric company [removed: that] [added: and] generates safe, affordable and reliable electricity for approximately 1.4 million retail customers in 11 of Arizona’s 15 counties.

To ensure [removed: our most vulnerable] customers [added: in need] are connected to these programs, we [removed: train and] partner with [removed: more than] [added: nearly] one hundred community action agencies across our service [removed: territory.][added: territory to train representatives who serve our shared customers.]

[removed: We have] [added: APS has] increased investment in fire mitigation efforts to clear defensible space around [removed: our] [added: its] infrastructure, continue ongoing system upgrades, build partnerships with government entities and first [removed: responders] [added: responders,] and educate customers and communities.

[removed: We] [added: APS] also increased spend on mitigating the risk associated with trees that could cause hazards, resulting in more of these trees being removed before they could cause outages or wildfires.

With [removed: recent] wildfire events in Hawaii, California, and across North [removed: America, we have] [added: America over the last few years, APS has] been devoting and [removed: will] [added: intends to] continue to devote substantial efforts to analyzing and developing enhancements to [removed: our] [added: its] systems and processes to mitigate fire risk within [removed: our] [added: its] service territory and communities, including by hardening our infrastructure, deploying new technologies where appropriate, increasing our awareness, implementing operational changes, and enhancing our wildfire response capabilities.

[added: APS uses fire modeling software to identify and calculate risk and target future] system improvement investments such as fire-resistant pole wrapping, wood to steel pole conversions, and additional remote-controllable field devices like reclosers and switches.

APS also implemented a [removed: PSPS] [added: public safety power shutoff (“PSPS”)] program on certain feeders that began in the 2024 fire season, leveraging the additional real-time analysis provided by the [removed: new modelling software, and has educated and is continuing education outreach to customers and communities that may potentially be impacted by the PSPS program.][added: modeling software.]

See Note [removed: 3] [added: 14] for more information.

[removed: Additionally,] APS was selected by [removed: the] DOE’s Grid Deployment Office (“GDO”) to receive up to $70 million in federal money for fire mitigation and grid infrastructure projects.

[removed: Dispatchable] [added: We achieve reliability, in part, through a blend of dispatchable resources, such as] natural gas [removed: generators] [added: and battery storage, that can] provide energy [removed: during times] when intermittent resources, such as [removed: solar] [added: wind] and [removed: wind,] [added: solar,] are [removed: insufficient to meet customer demand.][added: unavailable.]

APS’s customer affordability initiative includes internal opportunities, such as training and mentoring employees on identifying efficiency opportunities; maintaining [removed: an] inventory to take advantage of lower pricing and avoid expediting fees; entering into long-term contracts to hedge against price volatility, which has allowed APS to mitigate against procurement spend [removed: areas] [added: on critical items] such as transformers; and implementing automation technologies to enhance efficiencies and increase data-oriented decision making.

[removed: WEIM continues] [added: Until the transition] to [removed: be] [added: Markets+, APS will continue to participate in the WEIM as] a tool for creating savings for APS’s customers from the [removed: real-time,] [added: real-time only,] voluntary market.

APS [removed: continues to expect] [added: expects] that its participation in [added: the] WEIM [added: and future participation in Markets+] will lower its fuel and purchased-power costs, improve situational awareness for [removed: system] [added: systems] operations in the Western [removed: Interconnection power grid,] [added: Interconnection,] and improve integration of APS’s [removed: renewable] resources.

APS participated in market design and tariff development of Markets+, a day-ahead and real-time market offering from [removed: Southwest Power Pool (“SPP”).][added: SPP.]

In addition, APS is participating in the Western Resource Adequacy Program administered by Western Power Pool and [removed: is transitioning] [added: plans] to [removed: full binding] [added: transition to full-binding] participation [removed: as early as summer 2027.][added: in 2027 or 2028.]

[removed: In terms of generation affordability, every] [added: Every] three years, APS performs [added: an IRP,] a comprehensive [removed: study, called an Integrated Resource Plan (“IRP”),] [added: study] to identify what resources will be necessary to [removed: safely] [added: safely, reliably,] and [removed: reliably] [added: affordably] meet the demand and energy needs of its customers over the next 15 years.

In developing the IRP, APS considered how factors such as forecasted economic growth, impacts from weather, and new resource technology availability impact the amount and type of resources required to reliably [added: and affordably] meet customer needs.

These factors, among others, were used to develop a plan that identified a balanced mix of diverse [removed: energy generating] [added: energy-generating] resources to reliably serve customers’ future energy [removed: needs in the most affordable and sustainable manner possible.][added: needs.]

To help ensure competitive costs for resources procured by APS, APS regularly issues competitive bid solicitations through the ASRFP process, with the most recent [removed: ASRFPs] [added: ASRFP] being issued in [removed: 2022, 2023, and 2024.][added: 2025.]

APS continues to [removed: drive this initiative by identifying] [added: seek] opportunities to streamline its business processes, mitigate cost increases, increase employee retention, and improve customer satisfaction.

Our vision is to create a sustainable energy future for [removed: Arizona by providing reliable, affordable, and clean energy to our customers.][added: Arizona.]

[removed: APS has a] [added: APS’s] diverse portfolio of existing and planned [removed: resources, including solar, wind,] [added: resources includes biomass, biogas, coal,] energy storage, [removed: nuclear,] geothermal, [removed: biomass] [added: natural gas, nuclear, solar,] and [removed: biogas, that supports our commitment to clean energy.][added: wind.]

APS selects projects [added: out of ASRFPs] based on cost, ability to meet system [removed: requirements] [added: requirements,] and commercial viability, taking into consideration timing and likelihood of successful contracting and development.

[removed: On June 30, 2023,] [added: In terms of recent solicitations,] APS issued an ASRFP [removed: (the “2023 ASRFP”)] [added: on June 30, 2023,] pursuant to which APS procured [removed: nearly 7,300] [added: 3,606] MW of [removed: new] [added: battery storage, 517 MW of natural gas, 2,649 MW of solar, and 500 MW of wind] resources [added: expected] to be in service from 2026 to 2028.

Palo Verde, one of the nation’s largest [removed: carbon-free, clean] [added: carbon-free] energy resources, [removed: will continue to be] [added: serves as] a foundational part of APS’s resource portfolio.

The plant is a critical asset to the Southwest, generating more than 32 million MWh [removed: annually] – [added: enough power for roughly 3.4 million households, or approximately 8.5 million people.]

Its continued operation is important to a [removed: carbon-free and clean energy] [added: carbon-neutral] future for Arizona and the region, as a reliable, continuous, affordable resource and as a large contributor to the local economy.

Developing [removed: Clean Energy] Technologies

New Nuclear [removed: Generation][added: Generation.]

[removed: APS, along] [added: Along] with other Arizona electric utilities, [added: APS] is exploring [removed: new] [added: additional] nuclear generation to provide around-the-clock carbon-free energy to meet rising energy demands in Arizona.

APS has been monitoring emerging nuclear technologies, [removed: such as] [added: ranging from newer proposed and installed versions of large-scale reactors to] small modular nuclear [removed: reactors (“SMRs”).][added: reactors.]

[removed: SMRs] [added: Small modular nuclear reactors] are typically designed to generate 300 MW or less of energy per unit compared to, for example, the 1,400 MW per unit generated at Palo Verde.

The utilities have applied for a grant from [removed: the] DOE to begin preliminary exploration of a potential site for additional nuclear energy for Arizona.

Carbon [removed: Capture][added: Capture.]

Our other active subsidiaries are El Dorado and PNW Power.

Our mission is to serve customers with safe, reliable, and affordable energy.

We are committed to delivering operational excellence at the lowest cost possible while aspiring to lower carbon emissions over time.

As energy demand in Arizona continues to grow, we remain committed to delivering reliable service to our customers.

We have a goal of achieving top quartile reliability as compared to peers.

Key elements to delivering reliable service include resource and transmission planning to secure resource adequacy, planning and procuring resources to ensure sufficient reserve margins, distribution automation and resiliency investments, predictive and preventative maintenance programs, seasonal readiness programs, emergency preparedness, and securing a reliable supply chain.

Securing a reliable grid requires ongoing infrastructure investments in addition to investments to support new customer growth.

Balanced Energy Mix.

APS strives to procure a balanced energy mix, and we believe this provides the greatest reliability at the lowest cost possible while increasing resiliency.

evaluates the best mix of resources based on a changing operating environment, including changes in generation technology, economics, and policy impacts.

Additional natural gas capacity is necessary to support reliable service and meet increasing energy needs.

However, existing natural gas pipelines into Arizona are currently 100% committed.

As a result, in July 2025, APS executed a gas transportation precedent agreement to secure a long-term supply of natural gas.

The new pipeline is expected to be operational by late 2029 and will be owned and operated by a third-party.

APS also plans to add up to 2,000 MW of flexible natural gas generation to its portfolio, designed to help meet the growing around-the-clock energy needs in Arizona.

This generation is expected to serve existing customers and business-as-usual growth through our competitive ASRFP process as well as a new subscription model for large load customers, like data centers and large manufacturers.

This subscription model is a commercial construct designed to ensure growth pays for growth while protecting affordability for other customers.

APS owns or leases 29.1% of Units 1, 2, and 3 Palo Verde.

In June 2025, APS entered into agreements to purchase two of the three leased interests in Unit 2.

The two subject leased interests represented approximately 7% or 94 MW of Unit 2.

The transaction closed in September 2025, leaving one remaining lease for approximately 5.2% of Unit 2 that expires in 2033.

APS’s rate case application filed in 2025 (the “2025 Rate Case”) includes pro forma adjustments to account for these acquisitions.

Wildfire Efforts.

APS has educated and will continue education outreach to customers and communities that may potentially be impacted by the PSPS program.

Additionally, on May 12, 2025, Arizona Governor Hobbs signed into law a bill that requires Arizona electric utilities to develop and seek approval for wildfire mitigation plans and defines the standard of care with respect to wildfire-related claims by reference to such plans.

We are committed to keeping bills as low as possible for our customers while maintaining high levels of reliability.

Inflation has dramatically impacted the cost of goods and services in recent years as shown by the Consumer Price Index for All Urban Consumers (“CPI-U”), which from 2018 through 2024 rose nationally 24.9% and 32.1% in Phoenix.

Despite this, APS’s average residential rates remained well-below those inflation figures, rising 16.2% for the same period according to the U.S. Energy Information Administration.

Inflation has moderated from earlier highs, with CPI-U rising 2.7% nationally and 2.2% in Phoenix over the 12 months ended December 2025.

As a result of increased tariffs and supply chain constraints, APS amended several of its agreements from its ASRFP issued in 2023 to mitigate these cost impacts.

However, APS remains cautious of potential price increases as a result of current and proposed tariffs, which could lead to higher costs and supply chain constraints, while also monitoring the outcome of the recent U.S. Supreme Court’s decision regarding the validity of certain tariffs.

The customer affordability initiative also includes external opportunities, including a portfolio of customer programs designed to help customers reduce and manage their bills.

In the 2025 Rate Case, APS is also seeking to reduce cross-subsidization of customer classes and ensure that growth pays for growth by requesting modifications to its cost allocation methodologies.

APS’s IRP and competitive ASRFP processes serve important roles in providing reliable and affordable energy to APS’s customers.

The IRP process helps identify the amount and type of resources required to reliably meet customer needs, while the ASRFP process seeks to meet those needs in a competitive manner based on cost, ability to meet system requirements, and commercial viability.

APS has seen increasing demand from large load customers in recent years.

In the 2025 Rate Case, APS requested adjustments to rate designs and modification of cost allocation methodologies to ensure growth pays for growth.

In line with the 2025 Rate Case, APS has developed a subscription model it believes will allow for these large load customers to fund the incremental infrastructure needed to serve them through long-term contracts where they cover capital costs and assume development risks, accelerating their path to service and ensuring those infrastructure costs are borne by those customers rather than residential or small business customers.

There are also external opportunities that allow APS to deliver more affordable energy to customers, such as APS’s participation in western energy markets and programs.

APS is a funding party to the implementation phase of Markets+ and expects to go live in the market in October 2027.

Our strategy is to create a sustainable energy future for Arizona that delivers shareholder value and shared value by serving our customers with reliable, affordable, and clean energy.

APS’s focus remains on its customers and the communities it serves.

Accordingly, it is APS’s goal to achieve an industry-leading, best-in-class customer experience.

This multi-year objective includes incrementally improving APS’s J.D. Power (“JDP”) residential and business customer satisfaction ratings from the fourth to the top of second quartile for its customers.

For 2024, APS ranked at the top of the second quartile for large investor-owned utilities for both business and residential customers, with the residential results being APS’s highest rank and placement since 2016.

In furtherance of a customer-centric culture, APS employees have delivered an enhanced customer experience in recent years through a number of past and ongoing initiatives, such as improving the ease-of-use of APS’s automated phone system, improving the speed of answering customer calls, advancing phone advisor soft skill development through updated training curriculum, and adding 1,100-plus in-person payment locations, as well as introducing new customer payment channels.

Recently, APS redesigned its customer bills with the aim of increasing personalization and helping customers better understand their

energy use and find ways to save.

APS also implemented numerous enhancements to its website, including improving page-loading speeds, adding user-friendly dashboards, and making content more simple, relevant, and useful.

APS enhanced other customer touchpoints, such as communications throughout outages and the online outage center in addition to continuing to communicate with customers in their preferred channels about topics that matter most to them, such as reliability, energy-efficiency, financial assistance, the environment, and programs that enable them to design their own personalized energy experience.

Finally, APS continues to focus on employee learning, training, tools, and resources to ensure all employees understand their role in APS customers’ experiences.

Additionally, APS has implemented a variety of financial assistance programs to support customers struggling to pay their energy bills.

Among these assistance programs are discounts for qualified limited-income customers, including a new tier with larger discounts for APS’s lowest income customers added in the second quarter of 2024 and other non-income-based assistance programs, such as flexible payment arrangements and emergency utility bill assistance.

While our energy mix evolves, APS’s commitment to deliver reliable service to our customers remains.

APS is managing through significant growth in the Phoenix metropolitan area while experiencing supply chain issues similar to those experienced in other industries.

Planned investments will support operating and maintaining the grid, updating technology, accommodating customer growth, and enabling more renewable energy resources.

To prioritize reliability and meet substantial growth in customer energy needs, APS has developed a future-focused, strategic transmission plan (the “Ten-Year Transmission Plan”).

The Ten-Year Transmission Plan includes five critical transmission projects that comprise the APS strategic transmission portfolio, which represent a significant upgrade to our transmission system.

These five projects, along with other projects included in the Ten-Year Transmission Plan, will support growing energy needs, strengthen reliability, and allow for the connection of new resources.

Our advanced distribution management system allows operators to locate outages and control line devices remotely and helps them coordinate more closely with field crews to safely maintain an increasingly dynamic grid.

The system will also integrate a new meter data management system that will increase grid visibility and give customers access to more of their energy usage data.

APS completed implementation of fire modelling software that we are utilizing to more surgically identify and calculate risk and target future

For example, on August 14, 2024, APS filed a request with the ACC for a deferral order that would authorize APS to defer, for future recovery in rates, operations and maintenance expenses associated with wildfire management, including increased insurance costs.

APS cannot predict the outcome of this matter.

Maintaining reliability and affordability for customers during the clean energy transition is fundamental to APS’s strategy.

In addition to the previously added natural gas units at the modernized Ocotillo Power Plant in 2019 and efficiency improvements to gas units at the Redhawk, Sundance, and West Phoenix Power Plants in 2024, APS has contracted for two simple cycle combustion turbines (approximately 90 MW in total) at Sundance, which are expected to be in service in 2026, and eight simple cycle combustion turbines (approximately 397 MW in total) at Redhawk, which are expected to be in service in 2028.

In October 2021, APS announced plans to evaluate regional market solutions as part of the Western Markets Exploratory Group (“WMEG”).

As a member of WMEG, APS explored the potential for a staged approach to new market services, including day-ahead energy sales, transmission system expansion, and other power supply and grid solutions consistent with existing regulations and known and expected market design.

APS utilizes the work done by WMEG to help identify market solutions that can help achieve carbon reduction goals while supporting reliable, affordable service for customers.

APS went live with a new Energy Management System (“EMS”) in April 2024.

APS expects the new EMS to provide a better foundation which will improve future integration of the renewable and energy storage assets into APS’s generation resource portfolio, allowing APS to maximize the flexibility of its resources and fully engage in the Western Energy Imbalance Market (“WEIM”).

APS also believes it will better position APS to participate in market opportunities that develop over the next decade.

APS’s key elements to delivering reliable power include resource and transmission planning, sufficient reserve margins, partnering with customers to manage peak demand, fire mitigation, and operational preparedness, among others.

Seasonal readiness procedures at APS include inspections to ensure good material conditions and critical control system surveys.

APS also plans for the unexpected by conducting emergency operations drills and coordinating with federal, state, and local agencies on fire and emergency management.

APS continues to focus on mitigating the cost pressures related to inflation and other factors, such as tariffs.

Overall inflation grew by 1.6% in Phoenix and 2.9% nationally over the twelve months ended December 2024.

Although inflationary impacts to APS began to slow in 2024, APS is still managing the impacts high inflation.

Additionally, the implementation of recent and future tariffs could further escalate costs and introduce supply chain constraints.

There are also external opportunities under APS’s customer affordability initiative, such as APS’s participation in the WEIM.

See “Market and Credit Risks” in [added: Part II,] Item 7 above for a discussion of quantitative and qualitative disclosures about market risks.

We derive essentially all of our revenues and earnings from our [removed: wholly-owned] [added: principal] subsidiary, APS.

We own or lease [removed: 6,540] [added: 6,257] MW of regulated generation [removed: capacity] [added: capacity,] and we hold a mix of both long-term and short-term [removed: purchased power agreements] [added: PPAs] for additional capacity.

During [removed: 2024,] [added: 2025,] no single purchaser or user of energy accounted for more than [removed: 1.4%] [added: 1.9%] of our electric revenues.

[removed: ][added: ]

To serve its customers, APS obtains power through its various generation stations and through [removed: purchased power agreements.][added: PPAs.]

APS’s sources of energy by type used to supply energy to Native Load customers during [removed: 2024] [added: 2025] were approximately as follows:

[removed: ][added: ]

[removed: The] [added: In 2025, the] share of APS’s energy supply [removed: being] derived from clean resources was approximately [removed: 54% in 2024,] [added: 58%,] which includes energy from nuclear, [removed: renewables] [added: renewables,] and [removed: DSM.][added: DSM as well as PPAs with clean resources.]

APS [removed: currently] has a diverse portfolio of [removed: renewable] [added: existing and planned] resources, including [removed: biogas,] biomass, [added: biogas, coal, energy storage,] geothermal, [added: natural gas,] solar, and wind.

Among other strategies, APS intends to achieve [removed: these goals] [added: this goal] through various methods such as relying on Palo Verde, one of the nation’s largest producers of carbon-free energy; [removed: increasing clean energy resources, including renewables; developing] [added: seeking a balanced] energy [removed: storage; exiting from coal-generated electricity;] [added: mix;] managing demand with a modern interactive grid; promoting customer technology and energy efficiency; and optimizing regional resources.

[removed: Over this same period of time,] APS also intends to harden its infrastructure in order to improve [removed: climate] resiliency, which involves system and operational improvements aimed at reducing the impact of extreme weather events and other [removed: climate-related] disruptions upon APS’s operations.

For APS’s operations involving fossil-fuel electricity generation and electricity transmission and distribution, APS’s annual GHG inventory is reported to [removed: the] EPA under the EPA GHG Reporting Program.

In addition to reporting to [removed: the] EPA, we publicly report Scope 1 and [removed: 2, as well as a limited number of Scope 3,] [added: 2] GHG emissions.

This [added: performance] data is then communicated to the public in Pinnacle West’s annual Corporate Responsibility Report [removed: as performance data] and [removed: in CDP Reports, which are] [added: is] available on our website (*www.pinnaclewest.com/corporate-responsibility*).

The [removed: reports provide] [added: report provides] information related to the Company and its approach to sustainability and its workplace and environmental performance.

The information on Pinnacle West’s website, including [added: its] Corporate Responsibility [removed: Reports and CDP Reports,] [added: Report,] is not incorporated by reference into or otherwise a part of this report.

APS operates the plant and owns 29.1% of Palo Verde Units 1 and 3 and approximately [removed: 17%] [added: 23.9%] of Unit 2.

In addition, APS leases approximately [removed: 12.1%] [added: 5.2%] of Unit 2, resulting in a 29.1% combined ownership and leasehold interest in that unit.

At the end of the lease renewal [removed: periods,] [added: period,] APS will have the option to purchase the leased assets at their fair market value, extend the [removed: leases] [added: lease] for up to two years, or return the assets to the [removed: lessors.][added: lessor.]

See Note [removed: 17] [added: 12] for additional information regarding the Palo Verde Unit 2 sale leaseback transactions.

The Palo Verde participants have contracted for 100% of Palo Verde’s requirements for uranium concentrates through 2028 and [removed: 52%] [added: 70%] through 2029; 100% of Palo Verde’s requirements for conversion services through 2030 and 32% through 2031; 100% of Palo Verde’s requirements for enrichment services through 2028; and 100% of Palo Verde’s requirements for fuel fabrication through 2027 for Unit 2 and Unit 1 and 2028 for Unit 3.

Several legal proceedings followed challenging DOE’s withdrawal of its Yucca Mountain construction authorization application and the NRC’s cessation of its review of the Yucca [added: Mountain construction authorization application, which were consolidated into one matter at the U.S. Court of Appeals for the District of Columbia Circuit (the “D.C. Circuit”).]

APS has recovered costs for [removed: ten] [added: eleven] claims pursuant to the terms of the August 15, 2014 settlement agreement, for [removed: ten] [added: eleven] separate time periods during July 1, 2011 through October 31, [removed: 2023.][added: 2024.]

The DOE has approved and paid approximately [removed: $156.7] [added: $174.3] million for these claims (APS’s share is approximately [removed: $45.6] [added: $50.7] million).

In accordance with the [added: ACC’s decision from APS’s] 2017 [removed: Rate Case Decision,] [added: rate case,] this regulatory liability is being refunded to customers.

See Note [removed: 3.][added: 13.]

On October 31, [removed: 2024,] [added: 2025,] APS [removed: filed] [added: submitted] its [removed: eleventh] [added: twelfth] claim pursuant to the terms of the [removed: August 15, 2014,] settlement agreement in the amount of approximately [removed: $18] [added: $15.4] million (APS’s share is approximately [removed: $5.3] [added: $4.5] million).

In February [removed: 2025,] [added: 2026,] the DOE approved approximately [removed: $17.6] [added: $15.4] million of this claim.

[added: In June 2016, the D.C.] Circuit issued its final decision, rejecting all remaining legal challenges to the Continued Storage Rule.

*Palo Verde Liability and Insurance Matters* — See “Palo Verde Generating Station — Nuclear Insurance” in Note [removed: 10] [added: 14] for a discussion of the insurance maintained [added: for Palo Verde] by the Palo Verde participants, including [removed: APS, for Palo Verde.][added: APS.]

APS has a total entitlement from these plants of [removed: 3,573] [added: 3,722] MW.

In 2024, APS contracted for the addition of two combustion turbines (approximately 90 MW in total) at Sundance, which [removed: are expected to be in] [added: entered into] service in [removed: 2026,] [added: 2025,] and the addition of eight combustion turbines (approximately 397 MW total) at Redhawk, which are expected to be in service in 2028.

Following the closure of Unit 2, APS [removed: has] [added: had] a total entitlement from Cholla of 380 MW.

[added: APS had a total] entitlement from the Navajo Plant of 315 MW.

The Navajo Plant site [removed: is] [added: was] leased from the Navajo Nation and [removed: is also] subject to an easement from the federal government.

APS is currently recovering depreciation and a return on the net book value of its interest in the Navajo [removed: Plant over its previously estimated life through 2026.][added: Plant.]

APS will seek continued recovery in rates [removed: for] [added: or] the book value of its remaining investment in the plant.

See Note [removed: 10] [added: 8] for [added: details related to the regulatory treatment of these coal-fired plants and Note 14 for] information regarding APS’s coal mine reclamation obligations related to these coal-fired plants.

[removed: Solar Facilities][added: | *Solar:* | | | | | | | | | | | | | | | | | | | | | | | | | | |]

The following table summarizes APS’s [added: owned] renewable [removed: energy sources] [added: resources] currently in operation and under development as of the date of this report.

Pinnacle West is an investor-owned electric utility holding company based in Phoenix, Arizona

with consolidated assets of approximately $30 billion.

Since 1886, APS and its affiliates have provided energy and energy-related products to people and businesses throughout Arizona.

APS is Arizona’s largest and longest-serving electric company and generates safe, affordable electricity in 11 of Arizona’s 15 counties.

Our other active subsidiaries are El Dorado and PNW Power.

APS has an aspirational goal to be carbon-neutral by 2050, meaning that for any GHG emissions still produced by generation resources in 2050, APS will aim to offset these emissions elsewhere.

Maintaining a balanced and diverse portfolio of resources helps ensure continued reliable service to our customers in the most affordable manner possible.

Every three years, APS performs an IRP, a comprehensive study to identify what resources will be necessary to safely, reliably, and affordably meet the demand and energy needs of its customers over the next 15 years.

The latest IRP was released in 2023 and APS is currently developing its next IRP due to be filed with the ACC in August 2026.

To help ensure competitive costs for resources, APS regularly issues competitive bid solicitations through the ASRFP process, with the most recent ASRFP being issued in 2025.

These ASRFPs are open to bids for all resource types, including customer-scale (behind the meter) and utility-scale (in front of the meter) resources.

As energy demand in Arizona continues to grow, APS remains committed to delivering reliable and affordable service to its customers, with a goal of achieving top quartile reliability compared to its

peers.

Wildfire safety remains a critical focus for APS and other utilities.

APS has increased investment in fire mitigation efforts to clear defensible space around its infrastructure, continue ongoing system upgrades, build partnerships with government entities and first responders, and educate customers and communities.

In 2025, APS purchased two of the three leased interests.

The remaining lease for approximately 5.2% of Unit 2 expires in 2033.

APS is currently evaluating a proposed extension to the settlement to cover costs paid through December 31, 2028.

APS also plans to add up to 2,000 MW of flexible natural gas generation to its portfolio, designed to help meet the growing around-the-clock energy needs in Arizona.

APS ceased coal-burning operations at Cholla in March 2025 and formally retired Cholla Units 1 and 3 on April 30, 2025.

APS is currently recovering in rates a return on the net-book value of its interest in Cholla and associated depreciation costs.

In APS’s rate case application filed in 2025 (the “2025 Rate Case”), APS requested recovery in rates of the ongoing environmental remediation and CCR closure costs associated with Cholla and any remaining unrecovered plant costs.

The 2025 Rate Case also includes a request for an ongoing deferral order relating to anticipated increased environmental remediation costs relating to Cholla that may be incurred after the 2025 Rate Case proceeding.

APS Owned Renewable and Energy Storage Resources

APS owns various utility scale solar resources and DG systems developed through various ACC-approved programs as well as the ASRFP process.

Capacity amounts are approximate.

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

| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |

| | | | | | | Location | | | | | | Actual/Target Commercial Operation Date | | | | | | Net Capacity (MW) In Operation | | | | | | Net Capacity (MW) Planned/Under Development | | |

(a)This project met plant in service criteria as of December 31, 2025.

The following table summarizes APS’s owned energy storage currently in operation and under development as of the date of this report.

Capacity amounts are approximate and represent the maximum designed MW the site can provide for three hours, unless noted otherwise.

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

| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |

| | | | | | | Location | | | | | | Actual/Target Commercial Operation Date | | | | | | Net Capacity (MW) In Operation | | | | | | Net Capacity (MW) Planned/Under Development | | |

| *BESS:* | | | | | | | | | | | | | | | | | | | | | | | | | | |

| Paloma | | | | | | Gila Bend, AZ | | | | | | 2023 | | | | | | 17 | | | | | | | | |

| Cotton Center | | | | | | Gila Bend, AZ | | | | | | 2023 | | | | | | 17 | | | | | | | | |

| Hyder I | | | | | | Hyder, AZ | | | | | | 2023 | | | | | | 16 | | | | | | | | |

| Chino Valley (a) | | | | | | Chino Valley, AZ | | | | | | 2023 | | | | | | 19 | | | | | | | | |

Pinnacle West is a holding company incorporated in Arizona that conducts business through its subsidiaries.

APS is incorporated in Arizona and is a vertically-integrated electric utility that provides either retail or wholesale electric service to most of Arizona, with the major exceptions of about one-half of the Phoenix metropolitan area, the Tucson metropolitan area and Mohave County in northwestern Arizona.

Pinnacle West’s other active subsidiaries are El Dorado, an Arizona corporation, and PNW Power, a Delaware limited liability company.

BCE was a subsidiary of Pinnacle West, but was sold in January 2024.

Additional information related to these subsidiaries is provided later in this report.

*Utility Scale Renewables include energy from biogas, biomass, geothermal, solar, and wind.

Clean Energy Focus Initiatives

In response to climate change, APS has undertaken a number of initiatives to reduce carbon, including renewable energy procurement and development, and promotion of programs and rates that promote energy conservation, renewable energy use, and energy efficiency.

See “Energy Sources and Resource Planning — Current and Future Resources” below for details of these plans and initiatives.

In addition, in January 2020, APS announced its Clean Energy Commitment, a three-pronged approach aimed at ultimately eliminating carbon-emitting resources from its electric generation resource portfolio.

APS’s Clean Energy Commitment consists of three parts:

- A 2050 goal to provide 100% clean, carbon-free electricity;

- A 2030 target to achieve a resource mix that is 65% clean energy, with 45% of the generation portfolio coming from renewable energy; and

- A plan to exit from coal-fired generation by 2031.

Management takes into consideration climate change and other environmental risks in its strategy development, business planning, and enterprise risk management processes.

See Item 7, “Management’s Discussion and Analysis of Financial Condition and Results of Operations” for additional information about APS’s Clean Energy Commitment.

APS plans to continue its forest management programs aimed at reducing wildfires, as those risks become compounded by shorter, drier winters and longer, hotter summers as a result of climate change.

The leaseback was originally scheduled to expire at the end of 2015 and contained options to renew the leases or to purchase the leased property for fair market value at the end of the lease terms.

On July 7, 2014, APS exercised the fixed rate lease renewal options.

The exercise of the renewal options originally resulted in APS retaining the assets through 2023 under one lease and 2033 under the other two leases.

On April 1, 2021, APS executed an amendment relating to the lease agreement with the term ending in 2023.

The amendment extends the lease term for this lease through 2033 and changes the lease payment.

As a result of this amendment, APS will now retain the assets through 2033 under all three lease agreements.

Mountain construction authorization application, which were consolidated into one matter at the U.S. Court of Appeals for the District of Columbia Circuit (the “D.C. Circuit”).

In June 2016, the D.C.

On August 8, 2016, the D.C. Circuit denied a petition for rehearing.

APS plans to exit coal-fired generation as part of its portfolio of electricity generating resources, including Four Corners, by 2031.

APS has committed to end the use of coal at its remaining Cholla units during 2025.

APS purchased all of Cholla coal requirements from a coal supplier that mines the coal under long-term leases of coal reserves with the federal and state governments and private landholders.

APS elected not to extend the coal and transportation agreements that expired on December 31, 2024, as Cholla operations are expected to conclude in 2025.

APS had a total

The co-owners of the Navajo Plant and the Navajo Nation agreed that the Navajo Plant would remain in operation until December 2019 under the existing plant lease.

See Note 3 for details related to the resulting regulatory asset plus a return on the net book value as well as other costs related to retirement and closure, which are still being assessed and which may be material.

APS developed utility scale solar resources through the 180 MW ACC-approved AZ Sun Program, investing approximately $675 million in this program.

These facilities are owned by APS and are located in multiple locations throughout Arizona.

In addition to the AZ Sun Program, APS developed the 44 MW Red Rock Solar Plant and the 150 MW Agave Solar Plant, each of which it owns and operates, and has contracted for the construction of the 168 MW Ironwood Solar Plant.

APS owns and operates more than thirty small solar systems around the state.

Together they have the capacity to produce approximately 4 MW of renewable energy.

This fleet of solar systems includes a 3 MW facility located at the Prescott Airport and 1 MW of small solar systems in various locations across Arizona.

APS has also developed solar photovoltaic DG systems installed as part of the Community Power Project in Flagstaff, Arizona.

See “Business of Arizona Public Service Company — Environmental Matters” in [added: Part I,] Item 1 with regard to pending or threatened litigation and other disputes.

See Note [removed: 3] [added: 8] for ACC and FERC-related matters.

See Note [removed: 10] [added: 14] for information regarding environmental matters, Superfund–related matters and other disputes.

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

| Commission File Number | | | | | | Exact [removed: Name] [added: name] of [removed: Each Registrant] [added: registrant] as specified in its charter; State [added: or other jurisdiction] of [removed: Incorporation; Address;] [added: incorporation or organization; Address of principal executive offices, including zip code;] and [removed: Telephone Number] [added: Registrant’s telephone number, including area code] | | | | | | | | | | | | | | | IRS Employer Identification No. | | |

| | | | | | | Title Of Each Class | | | | | | Trading [removed: Symbol] [added: Symbol (s)] | | | | | | Name Of Each Exchange On Which Registered | | |

Indicate by check mark whether the registrant has submitted electronically [removed: and posted on its corporate Web site, if any,] every Interactive Data File required to be submitted [removed: and posted] pursuant to Rule 405 of Regulation S-T during the preceding 12 months (or for such shorter period that the registrant was required to submit [removed: and post] such [added: files).]

Indicate by check mark whether each registrant is a shell company (as defined in Rule 12b-2 of the [removed: Exchange] Act).

| ARIZONA PUBLIC SERVICE COMPANY | | | | | | $ | 0 | | as of June 30, [removed: 2024] [added: 2025] | | |

| PINNACLE WEST CAPITAL CORPORATION | | | Number of shares of common stock, no par value, outstanding as of February [removed: 20, 2025:] [added: 19, 2026:] | | | [removed: 119,099,064] [added: 120,905,390] | | |

| ARIZONA PUBLIC SERVICE COMPANY | | | Number of shares of common stock, $2.50 par value, outstanding as of February [removed: 20, 2025:] [added: 19, 2026:] | | | 71,264,947 | | |

Portions of Pinnacle West Capital Corporation’s definitive Proxy Statement relating to its Annual Meeting of Shareholders to be held on May [removed: 21, 2025] [added: 14, 2026] are incorporated by reference into Part III hereof.

Arizona Public Service Company meets the conditions set forth in General Instruction I(1)(a) and (b) of Form 10-K and is therefore filing this form with the reduced disclosure format allowed under [removed: that] General [removed: Instruction.][added: Instruction I(2).]

| [removed: [PART I](#i4188daee47a2424f9b9f03a13cf73aab_16)] [added: [PART](#i4188daee47a2424f9b9f03a13cf73aab_16) [I](#i4188daee47a2424f9b9f03a13cf73aab_16)] | | | | | | [3](#i4188daee47a2424f9b9f03a13cf73aab_16) | | |

| [Item 1A.](#i4188daee47a2424f9b9f03a13cf73aab_22) | | | [Risk Factors](#i4188daee47a2424f9b9f03a13cf73aab_22) | | | [removed: [33](#i4188daee47a2424f9b9f03a13cf73aab_22)] [added: [32](#i4188daee47a2424f9b9f03a13cf73aab_22)] | | |

| [Item 1B.](#i4188daee47a2424f9b9f03a13cf73aab_25) | | | [Unresolved Staff Comments](#i4188daee47a2424f9b9f03a13cf73aab_25) | | | [removed: [48](#i4188daee47a2424f9b9f03a13cf73aab_25)] [added: [46](#i4188daee47a2424f9b9f03a13cf73aab_25)] | | |

| [Item 1C.](#i4188daee47a2424f9b9f03a13cf73aab_28) | | | [Cybersecurity](#i4188daee47a2424f9b9f03a13cf73aab_28) | | | [removed: [48](#i4188daee47a2424f9b9f03a13cf73aab_28)] [added: [46](#i4188daee47a2424f9b9f03a13cf73aab_28)] | | |

| [Item 2.](#i4188daee47a2424f9b9f03a13cf73aab_31) | | | [Properties](#i4188daee47a2424f9b9f03a13cf73aab_31) | | | [removed: [50](#i4188daee47a2424f9b9f03a13cf73aab_31)] [added: [49](#i4188daee47a2424f9b9f03a13cf73aab_31)] | | |

| [removed: [PART II](#i4188daee47a2424f9b9f03a13cf73aab_43)] [added: [PART](#i4188daee47a2424f9b9f03a13cf73aab_43) [II](#i4188daee47a2424f9b9f03a13cf73aab_43)] | | | | | | [removed: [55](#i4188daee47a2424f9b9f03a13cf73aab_43)] [added: [54](#i4188daee47a2424f9b9f03a13cf73aab_43)] | | |

| [Item 5.](#i4188daee47a2424f9b9f03a13cf73aab_46) | | | [Market for Registrants’ Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities](#i4188daee47a2424f9b9f03a13cf73aab_46) | | | [removed: [55](#i4188daee47a2424f9b9f03a13cf73aab_46)] [added: [54](#i4188daee47a2424f9b9f03a13cf73aab_46)] | | |

| [Item 6.](#i4188daee47a2424f9b9f03a13cf73aab_49) | | | [\[Reserved\]](#i4188daee47a2424f9b9f03a13cf73aab_49) | | | [removed: [56](#i4188daee47a2424f9b9f03a13cf73aab_49)] [added: [55](#i4188daee47a2424f9b9f03a13cf73aab_49)] | | |

| [Item 7.](#i4188daee47a2424f9b9f03a13cf73aab_52) | | | [Management’s Discussion and Analysis of Financial Condition and Results of Operations](#i4188daee47a2424f9b9f03a13cf73aab_52) | | | [removed: [57](#i4188daee47a2424f9b9f03a13cf73aab_52)] [added: [56](#i4188daee47a2424f9b9f03a13cf73aab_52)] | | |

| [Item 7A.](#i4188daee47a2424f9b9f03a13cf73aab_76) | | | [Quantitative and Qualitative Disclosures About Market Risk](#i4188daee47a2424f9b9f03a13cf73aab_76) | | | [removed: [88](#i4188daee47a2424f9b9f03a13cf73aab_76)] [added: [84](#i4188daee47a2424f9b9f03a13cf73aab_76)] | | |

| [Item 8.](#i4188daee47a2424f9b9f03a13cf73aab_79) | | | [Financial Statements and Supplementary Data](#i4188daee47a2424f9b9f03a13cf73aab_79) | | | [removed: [89](#i4188daee47a2424f9b9f03a13cf73aab_79)] [added: [85](#i4188daee47a2424f9b9f03a13cf73aab_79)] | | |

| | | | [Pinnacle [removed: West Financial] [added: West](#i4188daee47a2424f9b9f03a13cf73aab_91) [Capital Corporation](#i4188daee47a2424f9b9f03a13cf73aab_91) [Financial] Statements](#i4188daee47a2424f9b9f03a13cf73aab_91) | | | [removed: [95](#i4188daee47a2424f9b9f03a13cf73aab_91)] [added: [91](#i4188daee47a2424f9b9f03a13cf73aab_91)] | | |

| [Item 9.](#i4188daee47a2424f9b9f03a13cf73aab_214) | | | [Changes in and [removed: Disagreements with] [added: Disagreements](#i4188daee47a2424f9b9f03a13cf73aab_214) [W](#i4188daee47a2424f9b9f03a13cf73aab_214)[ith] Accountants on Accounting and Financial Disclosure](#i4188daee47a2424f9b9f03a13cf73aab_214) | | | [removed: [202](#i4188daee47a2424f9b9f03a13cf73aab_214)] [added: [200](#i4188daee47a2424f9b9f03a13cf73aab_214)] | | |

| [Item 9A.](#i4188daee47a2424f9b9f03a13cf73aab_217) | | | [Controls and Procedures](#i4188daee47a2424f9b9f03a13cf73aab_217) | | | [removed: [202](#i4188daee47a2424f9b9f03a13cf73aab_217)] [added: [200](#i4188daee47a2424f9b9f03a13cf73aab_217)] | | |

| [Item 9B.](#i4188daee47a2424f9b9f03a13cf73aab_220) | | | [Other Information](#i4188daee47a2424f9b9f03a13cf73aab_220) | | | [removed: [203](#i4188daee47a2424f9b9f03a13cf73aab_220)] [added: [201](#i4188daee47a2424f9b9f03a13cf73aab_220)] | | |

| [Item 9C.](#i4188daee47a2424f9b9f03a13cf73aab_223) | | | [Disclosure Regarding Foreign Jurisdictions that Prevent Inspections](#i4188daee47a2424f9b9f03a13cf73aab_223) | | | [removed: [203](#i4188daee47a2424f9b9f03a13cf73aab_223)] [added: [201](#i4188daee47a2424f9b9f03a13cf73aab_223)] | | |

| [PART III](#i4188daee47a2424f9b9f03a13cf73aab_226) | | | | | | [removed: [203](#i4188daee47a2424f9b9f03a13cf73aab_226)] [added: [201](#i4188daee47a2424f9b9f03a13cf73aab_226)] | | |

| [Item 10.](#i4188daee47a2424f9b9f03a13cf73aab_229) | | | [Directors, Executive Officers and Corporate [removed: Governance of Pinnacle West](#i4188daee47a2424f9b9f03a13cf73aab_229)] [added: Governance](#i4188daee47a2424f9b9f03a13cf73aab_229)] | | | [removed: [203](#i4188daee47a2424f9b9f03a13cf73aab_229)] [added: [201](#i4188daee47a2424f9b9f03a13cf73aab_229)] | | |

| [Item 11.](#i4188daee47a2424f9b9f03a13cf73aab_232) | | | [Executive Compensation](#i4188daee47a2424f9b9f03a13cf73aab_232) | | | [removed: [203](#i4188daee47a2424f9b9f03a13cf73aab_232)] [added: [201](#i4188daee47a2424f9b9f03a13cf73aab_232)] | | |

| [Item 12.](#i4188daee47a2424f9b9f03a13cf73aab_235) | | | [Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters](#i4188daee47a2424f9b9f03a13cf73aab_235) | | | [removed: [203](#i4188daee47a2424f9b9f03a13cf73aab_235)] [added: [201](#i4188daee47a2424f9b9f03a13cf73aab_235)] | | |

| [Item 13.](#i4188daee47a2424f9b9f03a13cf73aab_238) | | | [Certain Relationships and Related Transactions, and Director Independence](#i4188daee47a2424f9b9f03a13cf73aab_238) | | | [removed: [205](#i4188daee47a2424f9b9f03a13cf73aab_238)] [added: [203](#i4188daee47a2424f9b9f03a13cf73aab_238)] | | |

| [Item 14.](#i4188daee47a2424f9b9f03a13cf73aab_241) | | | [Principal Accountant Fees and Services](#i4188daee47a2424f9b9f03a13cf73aab_241) | | | [removed: [205](#i4188daee47a2424f9b9f03a13cf73aab_241)] [added: [203](#i4188daee47a2424f9b9f03a13cf73aab_241)] | | |

| [PART IV](#i4188daee47a2424f9b9f03a13cf73aab_244) | | | | | | [removed: [206](#i4188daee47a2424f9b9f03a13cf73aab_244)] [added: [204](#i4188daee47a2424f9b9f03a13cf73aab_244)] | | |

| [Item 15.](#i4188daee47a2424f9b9f03a13cf73aab_247) | | | [Exhibits and Financial Statement Schedules](#i4188daee47a2424f9b9f03a13cf73aab_247) | | | [removed: [206](#i4188daee47a2424f9b9f03a13cf73aab_247)] [added: [204](#i4188daee47a2424f9b9f03a13cf73aab_247)] | | |

| [Item 16.](#i4188daee47a2424f9b9f03a13cf73aab_250) | | | [Form 10-K Summary](#i4188daee47a2424f9b9f03a13cf73aab_250) | | | [removed: [227](#i4188daee47a2424f9b9f03a13cf73aab_250)] [added: [216](#i4188daee47a2424f9b9f03a13cf73aab_250)] | | |

| [SIGNATURES](#i4188daee47a2424f9b9f03a13cf73aab_253) | | | | | | [removed: [228](#i4188daee47a2424f9b9f03a13cf73aab_253)] [added: [217](#i4188daee47a2424f9b9f03a13cf73aab_253)] | | |

[added: Part II,] Item 8 also includes Combined Notes to Consolidated Financial Statements.

| RES | | | [removed: Arizona] Renewable Energy Standard [removed: and Tariff] | | |

In addition to the Risk Factors described in [added: Part I,] Item 1A and in [added: Part II,] Item 7 — “Management’s Discussion and Analysis of Financial Condition and Results of Operations” of this report, these factors include, but are not limited to:

- [added: general economic conditions, such as tariffs, inflation, and other supply chain constraints, as well as] uncertainties associated with the current and future economic [removed: environment, including economic growth rates, labor market conditions, inflation, supply chain delays, increased expenses, volatile capital markets, or other unpredictable effects;][added: environment and conditions in Arizona; and]

See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

| PINNACLE WEST CAPITAL CORPORATION | | | | | | $ | 10,673,413,436 | | as of June 30, 2025 | | |

| | | | [A](#i4188daee47a2424f9b9f03a13cf73aab_115)[rizona](#i4188daee47a2424f9b9f03a13cf73aab_115) [P](#i4188daee47a2424f9b9f03a13cf73aab_115)[ublic](#i4188daee47a2424f9b9f03a13cf73aab_115) [S](#i4188daee47a2424f9b9f03a13cf73aab_115)[ervice](#i4188daee47a2424f9b9f03a13cf73aab_115) [Company](#i4188daee47a2424f9b9f03a13cf73aab_115) [Financial Statements](#i4188daee47a2424f9b9f03a13cf73aab_115) | | | [102](#i4188daee47a2424f9b9f03a13cf73aab_115) | | |

| AI | | | Artificial intelligence | | |

| ASRFP | | | All-source request for proposal | | |

| ASU | | | Accounting Standards Update | | |

| BESS | | | Battery energy storage system | | |

| CCRMU | | | Coal combustion residuals management unit | | |

| CCS | | | Carbon capture and sequestration or utilization controls | | |

| CERCLA or Superfund | | | Comprehensive Environmental Response Compensation and Liability Act | | |

| ELG | | | Effluent Limitation Guidelines | | |

| FRAM | | | Formula Rate Adjustment Mechanism | | |

| GAAP | | | Accounting principles generally accepted in the United States of America | | |

| IRP | | | Integrated Resource Plan | | |

| ITC | | | Investment Tax Credit | | |

| NAAQS | | | National Ambient Air Quality Standards | | |

| NPDES | | | National Pollutant Discharge Elimination System | | |

| NEIL | | | Nuclear Electric Insurance Limited | | |

| Ocotillo | | | Ocotillo Power Plant | | |

| PFAS | | | Per- and polyfluoroalkyl compounds | | |

| | | | | | |

| --- | --- | --- | --- | --- | --- |

| PTC | | | Production tax credit | | |

| RCRA | | | Resource Conservation and Recovery Act | | |

| ROD | | | Record of Decision | | |

| ROO | | | Recommended Opinion and Order | | |

| SEC | | | United States Securities and Exchange Commission | | |

| SPP | | | Southwest Power Pool | | |

| SRB | | | System Reliability Benefit Mechanism | | |

| WEIM | | | Western Energy Imbalance Market | | |

iii

- the impacts of federal, state, and local laws, judicial decisions, statutes, regulations, and FERC, NRC, EPA, ACC, and other agency requirements, including as they are changed by legislative and regulatory action as well as executive orders, such as those relating to tax, environment, energy, nuclear plants, and deregulation of the retail electric market;

- our operation of Palo Verde is subject to substantial regulatory oversight and potentially significant liabilities and capital expenditures;

- we are subject to numerous environmental laws and changes to existing laws, or new laws, may increase our costs and impact our business;

- co-owners of our jointly owned generation and transmission facilities may have unaligned goals;

- deregulation of the electric industry and other factors, such as large customers developing large, utility scale generation to serve their energy needs, may result in increased competition;

- wildfires, including those arising as a result of climate change, extreme weather events, or the expansion of the wildland urban interface;

- our ability and efforts to meet current and anticipated future needs for generation and transmission and distribution facilities in our region at reliable levels, including factors affecting our ability to acquire and develop new resources to serve this load as well as difficulties in accurately forecasting load growth, particularly from high load energy users;

- the development of new technologies and the impact they have on the retail and wholesale electricity market and the impacts of our adoption or failure to adopt such technologies;

- the availability and retention of qualified personnel and the need to negotiate collective bargaining agreements with union employees;

files).

| PINNACLE WEST CAPITAL CORPORATION | | | | | | $ | 8,663,553,568 | | as of June 30, 2024 | | |

| | | | [APS Financial Statements](#i4188daee47a2424f9b9f03a13cf73aab_115) | | | [106](#i4188daee47a2424f9b9f03a13cf73aab_115) | | |

| AC | | | Alternating Current | | |

| DOI | | | United States Department of the Interior | | |

| EGU | | | Electric generating unit | | |

| OCI | | | Other comprehensive income | | |

- current and future economic conditions in Arizona, such as the housing market and overall business and regulatory environment;

- our ability to manage capital expenditures and operations and maintenance costs while maintaining reliability and customer service levels;

- power plant and transmission system performance and outages;

- competition in retail and wholesale power markets;

- regulatory and judicial decisions, developments, and proceedings;

- new legislation, ballot initiatives, and regulation or interpretations of existing legislation or regulations, including those relating to environmental requirements, regulatory and energy policy, nuclear plant operations, and potential deregulation of retail electric markets;

- fuel and water supply availability;

- the ability of APS to meet renewable energy and energy efficiency mandates and recover related costs;

- the ability of APS to achieve its clean energy goals (including a goal by 2050 of 100% clean, carbon-free electricity) and, if these goals are achieved, the impact of such achievement on APS, its customers, and its business, financial condition, and results of operations;

- the development of new technologies which may affect electric sales or delivery, including as a result of delays in the development and application of new technologies;

- environmental, economic, and other concerns surrounding coal-fired generation, including regulation of GHG;

- new accounting requirements or new interpretations of existing requirements;

- our ability to meet the anticipated future need for additional generation and associated transmission facilities in our region;

- restrictions on dividends or other provisions in our credit agreements and ACC orders.

Neither Pinnacle West nor APS has received written comments regarding its periodic or current reports from the SEC staff that were issued 180 days or more preceding the end of its [removed: 2024] [added: 2025] fiscal year and that remain unresolved.

To that end, the Company implements a robust risk management, strategy, and governance regime aimed at [removed: ensuring effective] [added: implementing] controls [removed: are in place] to identify, mitigate, remediate, and communicate cyber threats at appropriate levels within the organization.

[removed: The Director of Cybersecurity has more than twenty years of experience in] information technology and cybersecurity roles, with more than ten of those years at the Company.

[added: Once an incident meets certain criteria, the Company’s Cybersecurity Incident Command or, in the case of a potentially severe threat that could] impact the entire Company, the Corporate Emergency Operations Center is activated and formal response procedures are followed to address the incident.

The Enterprise Risk Management Program is overseen by an executive committee (the “Executive Risk Committee”), which meets at least quarterly and is comprised of members holding executive leadership positions in the Company, including the [removed: Chairman] [added: Chairman, President,] and Chief Executive Officer, [removed: President,] and other Executive and Senior Vice Presidents, and is chaired and sponsored by the Chief Financial Officer.

Finally, the Nuclear and Operating Committee of the Company’s Board of Directors provides ultimate oversight of cybersecurity risk and also receives briefings [added: in-person or virtually] at least twice per year from the Cybersecurity Group, and notable [removed: audit findings relating to cybersecurity are aggregated and provided to the Board of Directors’ Audit Committee.]

To date, we do not believe there have been [removed: risks from cybersecurity threats, including as a result of] any previous cybersecurity [removed: incidents,] [added: incidents] that have materially affected or are reasonably likely to materially affect Pinnacle West or APS.

If a significant cybersecurity event or incident were to occur, our ability to fulfill our critical business functions [removed: and] [added: could be materially impacted, which could materially adversely affect] our [removed: business strategy,] results of [removed: operations,] [added: operations] and financial [removed: condition could all be materially impacted.][added: conditions.]

See the risk factor entitled, “We are subject to cybersecurity risks and risks of unauthorized access to our systems that could adversely affect our business and financial condition” in [added: Part I,] Item 1A—Risk Factors for more information.

The Director of Cybersecurity has more than twenty years of experience in

Cybersecurity is among the enterprise risks assessed annually and was identified as a top risk in 2025.

audit findings relating to cybersecurity are aggregated and provided to the Board of Directors’ Audit Committee.

Once an incident meets certain criteria, the Company’s Cybersecurity Incident Command or, in the most severe cases that

For 2024, cybersecurity was identified as a risk.

APS’s portfolio of owned generating facilities [added: in commercial operation] as of [removed: December 31, 2024] [added: the date of this report] is provided in the table below:

| Total Steam | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [removed: 1,350] [added: 970] | | |

| Redhawk | | | | | | 2 | | | | | | | | | | | | Gas | | | | | | Load Following | | | | | | [removed: 1,136] [added: 1,140] | | |

| Total Combined Cycle | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [removed: 2,010] [added: 2,014] | | |

| Sundance | | | | | | [removed: 10] [added: 12] | | | | | | | | | | | | Gas | | | | | | Peaking | | | | | | [removed: 430] [added: 520] | | |

| Yucca 1, 2, [removed: 3] [added: 3, 5, 6] | | | | | | [removed: 3] [added: 5] | | | | | | | | | | | | Gas | | | | | | Peaking | | | | | | [removed: 93] [added: 183] | | |

| Total Combustion Turbine | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [removed: 1,618] [added: 1,708] | | |

| [removed: Solar: (d)] [added: Solar:] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |

| Cotton Center | | | | | | [removed: 1] | | | | | | | | | | | | Solar | | | | | | As Available | | | | | | 17 | | |

| Hyder I | | | | | | [removed: 1] | | | | | | | | | | | | Solar | | | | | | As Available | | | | | | 17 | | |

| Paloma | | | | | | [removed: 1] | | | | | | | | | | | | Solar | | | | | | As Available | | | | | | 17 | | |

| Chino Valley | | | | | | [removed: 1] | | | | | | | | | | | | Solar | | | | | | As Available | | | | | | 20 | | |

| Gila Bend | | | | | | [removed: 1] | | | | | | | | | | | | Solar | | | | | | As Available | | | | | | 36 | | |

| Hyder II | | | | | | [removed: 1] | | | | | | | | | | | | Solar | | | | | | As Available | | | | | | 14 | | |

| Foothills | | | | | | [removed: 1] | | | | | | | | | | | | Solar | | | | | | As Available | | | | | | 38 | | |

| Luke AFB | | | | | | [removed: 1] | | | | | | | | | | | | Solar | | | | | | As Available | | | | | | 11 | | |

| Desert Star | | | | | | [removed: 1] | | | | | | | | | | | | Solar | | | | | | As Available | | | | | | 10 | | |

| Red Rock | | | | | | [removed: 1] | | | | | | | | | | | | Solar | | | | | | As Available | | | | | | 44 | | |

| Agave Solar | | | | | | [removed: 1] | | | | | | | | | | | | Solar | | | | | | As Available | | | | | | 150 | | |

| APS Owned Distributed Energy | | | | | | | | | | | | | | | | | | Solar | | | | | | As Available | | | | | | [removed: 38] [added: 41] | | |

| Total Solar | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [removed: 416] [added: 419] | | |

| Total Capacity | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [removed: 6,540] [added: 6,257] | | |

See “Business of Arizona Public Service Company — Energy Sources and Resource Planning — Generation Facilities — Nuclear” in [added: Part I,] Item 1 for details regarding leased interests in Palo Verde.

See “Business of Arizona Public Service Company” in [added: Part I,] Item 1 for a map detailing the location of APS’s major power plants and principal transmission lines.

Current Facilities. As of January [removed: 24, 2025,] [added: 22, 2026,] APS’s transmission facilities consist of approximately [removed: 5,817] [added: 5,939] pole miles of overhead lines and approximately 86 miles of underground lines, [removed: 5,757] [added: 5,792] miles of which are located in Arizona.

APS’s distribution facilities consist of approximately [removed: 11,317] [added: 11,321] miles of overhead lines and approximately [removed: 24,031] [added: 24,425] miles of underground primary cable [removed: (20,893] [added: (21,301] when excluding abandoned conductor), all of which are located in Arizona.

APS also owns and maintains [removed: 485] [added: 477] substations, including both transmission and distribution yards.

The following table shows APS’s jointly-owned interests in those transmission facilities recorded on the Consolidated Balance Sheets at December 31, [removed: 2024:][added: 2025:]

| Arizona Nuclear Power Project 500kV System | | | [removed: 33.3] [added: 33.1] | | % |

| Navajo Southern System | | | [removed: 24.7] [added: 25.1] | | % |

| Palo Verde — Yuma 500kV System | | | [removed: 25.5] [added: 16.1] | | % |

| Four Corners Switchyards | | | [removed: 58.0] [added: 56.9] | | % |

| Phoenix — Mead System | | | [removed: 17.1] [added: 17.5] | | % |

In APS’s [removed: 2025] [added: 2026] Ten-Year [added: Transmission] Plan, APS projects it will develop [removed: 184] [added: 263] miles of new transmission lines over the next 10 years.

Additionally, APS plans to upgrade [removed: 687] [added: 725] miles of existing transmission lines over the same [added: horizon.]

The co-owners and the Navajo Nation executed a lease extension on November 29, 2017, that [removed: allows] [added: allowed] for decommissioning activities to begin after the plant ceased operations.

See “Business of Arizona Public Service Company — Energy Sources and Resource Planning — Generation Facilities — Coal-Fueled Generating Facilities — Four Corners” in [added: Part I,] Item 1 for additional information about the Four Corners right-of-way and lease matters.

Certain portions of [removed: our] [added: APS’s] transmission lines are located on Indian lands pursuant to rights-of-way that are effective for specified periods.

Some of these rights-of-way have expired and [removed: our] renewal applications have not yet been acted upon by the appropriate Indian tribes or federal agencies.

In recent negotiations, certain of the affected Indian tribes have required payments substantially in excess of [added: historical] amounts [removed: that we have] paid in the past for such rights-of-way.

Energy Storage Facilities

APS’s portfolio of owned energy storage facilities in commercial operation as of the date of this report is provided in the table below.

Capacity amounts are approximate and represent the maximum designed MW the site can provide for three hours, unless noted otherwise.

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

| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |

| | | | | | | Location | | | | | | Owned Capacity | | |

| BESS: | | | | | | | | | | | | | | |

| Paloma | | | | | | Gila Bend, AZ | | | | | | 17 | | |

| Cotton Center | | | | | | Gila Bend, AZ | | | | | | 17 | | |

| Hyder I | | | | | | Hyder, AZ | | | | | | 16 | | |

| Chino Valley (a) | | | | | | Chino Valley, AZ | | | | | | 19 | | |

| Hyder II | | | | | | Hyder, AZ | | | | | | 14 | | |

| Foothills | | | | | | Yuma, AZ | | | | | | 35 | | |

| Gila Bend | | | | | | Gila Bend, AZ | | | | | | 32 | | |

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

| Desert Star | | | | | | Buckeye, AZ | | | | | | 10 | | |

| Red Rock (a) | | | | | | Red Rock, AZ | | | | | | 41 | | |

| Total Energy Storage | | | | | | | | | | | | 201 | | |

(a) Capacity amounts represent the maximum designed MW the site can provide for four hours.

| | | | | | |

The 2026 Ten-Year Plan includes critical transmission projects that represent significant upgrades to our transmission system.

These upgrade projects, along with other projects included in the 2026 Ten Year Transmission Plan, are designed to support growing energy needs, strengthen reliability, and allow for the connection of new resources.

| Cholla 1,3 | | | | | | 2 | | | | | | | | | | | | Coal | | | | | | Base Load | | | | | | 380 | | |

| Yucca 5, 6 | | | | | | 2 | | | | | | | | | | | | Gas | | | | | | Peaking | | | | | | 90 | | |

(d)See “Business of Arizona Public Service Company — Energy Sources and Resource Planning — Energy Storage” above for details related to APS’s energy storage facilities and agreements.

See “Business of Arizona Public Service Company — Environmental Matters” in Item 1 with respect to matters having a possible impact on the operation of certain of APS’s generating facilities.

| Agua Fria Switchyard | | | 10.0 | | % |

horizon.

The 2025 Ten-Year Plan includes a 28-mile 500kV line from the Jojoba substation to the Rudd substation.

The purpose of this 500kV line project is to bring in a new source to the west and southwest parts of the Phoenix metropolitan area which is experiencing rapid economic development.

This new source will provide customers in the area greater access to a diverse mix of resources from around the region.

Additionally, the 2025 Ten-Year Plan includes the rebuild of both Four Corners to Pinnacle Peak 345kV lines which span 289 miles each.

This rebuild will replace aging towers to ensure continued reliability and safety, increase important capability to the Metro Phoenix area, and improve access to a diverse mix of resources from the Four Corners region throughout the Southwest.

The 2025 Ten-Year Plan includes numerous projects with the purpose to interconnect new renewable energy resources to the transmission system.

The executive officers, their ages at February 25, [removed: 2025,] [added: 2026,] current positions and principal occupations for the past five years are as follows:

| Name | | | [added: | | |] Age | | | | | | Position | | | | | | Period | | |

| [removed: Jeffrey B. Guldner (a)] [added: Theodore N. Geisler] | | | [removed: 59] | | | [added: 47] | | | [added: | | |] Chairman of the Board, Chief Executive Officer and President of Pinnacle West [added: and APS] | | | | | | [removed: 2019-Present] [added: 2025-Present] | | |

| [added: Adam C. Heflin] | | | | | | [added: 62] | | | [removed: Chairman of the Board] [added: | | | Executive Vice President] and Chief [removed: Executive Officer] [added: Nuclear Officer, Palo Verde,] of APS | | | | | | 2022-Present | | |

| Elizabeth A. Blankenship | | | [removed: 53] | | | [added: 54] | | | [added: | | |] Vice President, Controller and Chief Accounting Officer of Pinnacle West and APS | | | | | | 2019-Present | | |

| Andrew D. Cooper | | | [removed: 46] | | | [added: 47] | | | [added: | | |] Senior Vice President and Chief Financial Officer of Pinnacle West and APS | | | | | | 2022-Present | | |

| | | | | | | | | | [added: | | |] Vice President and Treasurer of Pinnacle West and APS | | | | | | 2020-2022 | | |

| Jose L. Esparza | | | [removed: 50] | | | [added: 51] | | | [added: | | |] Senior Vice President, Public Policy of APS | | | | | | 2022-Present | | |

| | | | | | | | | | [added: | | |] Vice President, Regulatory of APS | | | | | | 2022 | | |

| | | | | | | | | | [added: | | |] Officer and Senior Vice President, Customer Engagement and Information Technology of Southwest Gas | | | | | | 2019-2021 | | |

| [removed: Theodore N. Geisler (a)] | | | [removed: 46] | | | | | | [added: | | |] President of [removed: APS, Director on the] [added: APS; Director,] Pinnacle West and APS Boards of Directors | | | | | | [removed: 2024-Present] [added: 2024-2025] | | |

| | | | | | | | | | [added: | | |] President of APS | | | | | | [removed: 2022-Present] [added: 2022-2024] | | |

| | | | | | | | | | [added: | | |] Senior Vice President and Chief Financial Officer of Pinnacle West and APS | | | | | | 2020-2022 | | |

| [added: Jacob Tetlow] | | | | | | [added: 53] | | | [added: | | | Executive] Vice President and Chief [removed: Information] [added: Operating] Officer of APS | | | | | | [removed: 2018-2020] [added: 2024-Present] | | |

| | | | | | | | | | [added: | | |] Chief Executive Officer of Wolf Creek Nuclear Operating Corporation | | | | | | 2014-2019 | | |

| [removed: Paul J. Mountain] [added: Christopher R. Bauer] | | | [removed: 47] | | | [added: 50] | | | [added: | | |] Vice [removed: President, Finance] [added: President] and [removed: Planning] [added: Treasurer] of Pinnacle West and APS | | | | | | 2024-Present | | |

| | | | | | | | | | [added: | | |] Vice [removed: President, Finance and Treasurer] [added: President] of [added: Law of] Pinnacle West and APS | | | | | | [removed: 2022-2024] [added: 2022-2025] | | |

| | | | | | | | | | [added: | | | Senior] Vice [removed: President, Finance] [added: President] and [removed: Planning] [added: General Counsel] of Pinnacle West and APS | | | | | | [removed: 2020-2022] [added: 2025-2026] | | |

| [added: Shirley A. Baum] | | | | | | [added: 52] | | | [added: | | |] Senior Vice [removed: President] [added: President, Corporate Secretary] and General Counsel of Pinnacle West and APS | | | | | | [removed: 2018-2021] [added: 2026-Present] | | |

| | | | | | | | | | [added: | | |] Executive Vice President, Operations of APS | | | | | | 2021-2024 | | |

| | | | | | | | | | [added: | | |] Senior Vice President, Non-Nuclear Operations of APS | | | | | | 2020-2021 | | |

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

| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |

| | | | | | | | | | | | | Deputy General Counsel of Pinnacle West | | | | | | 2019-2022 | | |

| | | | | | | | | | | | | Director, Corporate Finance and Assistant Treasurer of Duke Energy Corporation | | | | | | 2021-2024 | | |

| | | | | | | | | | | | | Director, Credit and Capital Markets of Duke Energy Corporation | | | | | | 2017-2021 | | |

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

| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |

| | | | | | | | | | Chairman of the Board, Chief Executive Officer and President of APS | | | | | | 2021-2022 | | |

| | | | | | | | | | Chairman of the Board and Chief Executive Officer of APS | | | | | | 2020-2021 | | |

| | | | | | | | | | President of APS | | | | | | 2018-2020 | | |

| | | | | | | | | | Executive Vice President, Public Policy of Pinnacle West | | | | | | 2017-2019 | | |

| | | | | | | | | | General Manager, Accounting Operations of APS | | | | | | 2019-2019 | | |

| | | | | | | | | | Director, Accounting Operations of APS | | | | | | 2014-2019 | | |

| | | | | | | | | | Director, Corporate Finance of Consolidated Edison Company of New York, Inc. | | | | | | 2017-2020 | | |

| | | | | | | | | | Vice President, Customer Engagement of Southwest Gas | | | | | | 2012-2019 | | |

| Adam C. Heflin | | | 61 | | | | | | Executive Vice President and Chief Nuclear Officer, PVGS, of APS | | | | | | 2022-Present | | |

| | | | | | | | | | General Manager, Finance of Pinnacle West | | | | | | 2017-2020 | | |

| Robert E. Smith | | | 55 | | | | | | Executive Vice President, Chief Legal Officer and Chief Development Officer of Pinnacle West and APS | | | | | | 2025-Present | | |

| | | | | | | | | | Executive Vice President, General Counsel and Chief Development Officer of Pinnacle West and APS | | | | | | 2021-2025 | | |

| Jacob Tetlow | | | 52 | | | | | | Executive Vice President and Chief Operating Officer of APS | | | | | | 2024-Present | | |

| | | | | | | | | | Vice President, Transmission and Distributions Operations of APS | | | | | | 2017-2020 | | |

(a) On December 12, 2024, Pinnacle West announced that Jeffrey B.

Guldner will retire from his position as Chairman of the Board, President, Chief Executive Officer and member of the Board of Directors of Pinnacle West and Chairman of the Board, Chief Executive Officer and member of the Board of Directors of APS, effective April 1, 2025.

On April 1, 2025, Theodore N.

Geisler will replace Mr. Guldner as Chairman of the Board, President, and Chief Executive Officer of Pinnacle West and Chairman of the Board and Chief Executive Officer of APS.

He will continue to serve as President of APS and as a director on the Pinnacle West and APS Boards of Directors.

At the close of business on February [removed: 20, 2025,] [added: 19, 2026,] Pinnacle West’s common stock was held of record by approximately [removed: 13,686] [added: 12,926] shareholders.

At December 31, [removed: 2024,] [added: 2025,] APS did not have any outstanding preferred stock.

This graph compares the cumulative total shareholder return on Pinnacle West’s common stock during the five years ended December 31, [removed: 2024,] [added: 2025,] to the cumulative total returns on the S&P 500 Index and the Edison Electric [added: Institute] Index.

The comparison assumes that $100 was invested on December 31, [removed: 2019,] [added: 2020,] in Pinnacle West’s common stock and in each of the indices shown and that all of the dividends were reinvested.

[removed: ][added: ]

| Company/Index | | | | | | [removed: 2019] [added: 2020] | | | | | | [removed: 2020] [added: 2021] | | | | | | [removed: 2021] [added: 2022] | | | | | | [removed: 2022] [added: 2023] | | | | | | [removed: 2023] [added: 2024] | | | | | | [removed: 2024] [added: 2025] | | |

| Pinnacle West Common Stock | | | | | | $100 | | | | | | $92 | | | | | | [removed: $85] [added: $104] | | | | | | [removed: $96] [added: $103] | | | | | | [removed: $95] [added: $127] | | | | | | [removed: $117] [added: $138] | | |

| Edison Electric Institute Index | | | | | | $100 | | | | | | [removed: $99] [added: $117] | | | | | | [removed: $116] [added: $118] | | | | | | [removed: $117] [added: $108] | | | | | | [removed: $107] [added: $129] | | | | | | [removed: $127] [added: $144] | | |

| S&P 500 Index | | | | | | $100 | | | | | | $129 | | | | | | $105 | | | | | | $133 | | | | | | $166 | | | | | | $195 | | |

| S&P 500 Index | | | | | | $100 | | | | | | $118 | | | | | | $152 | | | | | | $125 | | | | | | $157 | | | | | | $197 | | |

| [Management’s Report on Internal Control over Financial Reporting (Pinnacle West Capital Corporation)](#i4188daee47a2424f9b9f03a13cf73aab_85) | | | [removed: [90](#i4188daee47a2424f9b9f03a13cf73aab_85)] [added: [86](#i4188daee47a2424f9b9f03a13cf73aab_85)] | | |

| [Report of Independent Registered Public Accounting Firm](#i4188daee47a2424f9b9f03a13cf73aab_88) (PCAOB ID No. 34) | | | [removed: [91](#i4188daee47a2424f9b9f03a13cf73aab_88)] [added: [87](#i4188daee47a2424f9b9f03a13cf73aab_88)] | | |

| [Pinnacle West Consolidated Statements of Income [removed: for 20](#i4188daee47a2424f9b9f03a13cf73aab_91)[24](#i4188daee47a2424f9b9f03a13cf73aab_91)[, 20](#i4188daee47a2424f9b9f03a13cf73aab_91)[23](#i4188daee47a2424f9b9f03a13cf73aab_91) [and 20](#i4188daee47a2424f9b9f03a13cf73aab_91)[22](#i4188daee47a2424f9b9f03a13cf73aab_91)] [added: for](#i4188daee47a2424f9b9f03a13cf73aab_91) [](#i4188daee47a2424f9b9f03a13cf73aab_91)[2025, 2024 and 2023](#i4188daee47a2424f9b9f03a13cf73aab_91)] | | | [removed: [95](#i4188daee47a2424f9b9f03a13cf73aab_91)] [added: [91](#i4188daee47a2424f9b9f03a13cf73aab_91)] | | |

| [Pinnacle West Consolidated Statements of Comprehensive Income [removed: for 20](#i4188daee47a2424f9b9f03a13cf73aab_94)[24](#i4188daee47a2424f9b9f03a13cf73aab_94)[, 20](#i4188daee47a2424f9b9f03a13cf73aab_94)[23](#i4188daee47a2424f9b9f03a13cf73aab_94) [and 20](#i4188daee47a2424f9b9f03a13cf73aab_94)[22](#i4188daee47a2424f9b9f03a13cf73aab_94)] [added: for](#i4188daee47a2424f9b9f03a13cf73aab_94) [](#i4188daee47a2424f9b9f03a13cf73aab_94)[2025, 2024 and 2023](#i4188daee47a2424f9b9f03a13cf73aab_91)] | | | [removed: [96](#i4188daee47a2424f9b9f03a13cf73aab_94)] [added: [92](#i4188daee47a2424f9b9f03a13cf73aab_94)] | | |

| [Pinnacle West Consolidated Balance Sheets as of December [removed: 31, 20](#i4188daee47a2424f9b9f03a13cf73aab_97)[24](#i4188daee47a2424f9b9f03a13cf73aab_97) [and 20](#i4188daee47a2424f9b9f03a13cf73aab_97)[23](#i4188daee47a2424f9b9f03a13cf73aab_97)] [added: 31,](#i4188daee47a2424f9b9f03a13cf73aab_97) [2025 and](#i4188daee47a2424f9b9f03a13cf73aab_97) [20](#i4188daee47a2424f9b9f03a13cf73aab_97)[24](#i4188daee47a2424f9b9f03a13cf73aab_97)] | | | [removed: [97](#i4188daee47a2424f9b9f03a13cf73aab_97)] [added: [93](#i4188daee47a2424f9b9f03a13cf73aab_97)] | | |

| [Pinnacle West Consolidated Statements of Cash Flows [removed: for 20](#i4188daee47a2424f9b9f03a13cf73aab_100)[24](#i4188daee47a2424f9b9f03a13cf73aab_100)[, 20](#i4188daee47a2424f9b9f03a13cf73aab_100)[23](#i4188daee47a2424f9b9f03a13cf73aab_100) [and 20](#i4188daee47a2424f9b9f03a13cf73aab_100)[22](#i4188daee47a2424f9b9f03a13cf73aab_100)] [added: for](#i4188daee47a2424f9b9f03a13cf73aab_100) [2025, 2024 and 2023](#i4188daee47a2424f9b9f03a13cf73aab_91)] | | | [removed: [99](#i4188daee47a2424f9b9f03a13cf73aab_100)] [added: [95](#i4188daee47a2424f9b9f03a13cf73aab_100)] | | |

| [Pinnacle West Consolidated Statements of Changes in Equity [removed: for 20](#i4188daee47a2424f9b9f03a13cf73aab_103)[24](#i4188daee47a2424f9b9f03a13cf73aab_103)[, 20](#i4188daee47a2424f9b9f03a13cf73aab_103)[23](#i4188daee47a2424f9b9f03a13cf73aab_103) [and 20](#i4188daee47a2424f9b9f03a13cf73aab_103)[22](#i4188daee47a2424f9b9f03a13cf73aab_103)] [added: for](#i4188daee47a2424f9b9f03a13cf73aab_103) [](#i4188daee47a2424f9b9f03a13cf73aab_103)[2025, 2024 and 2023](#i4188daee47a2424f9b9f03a13cf73aab_91)] | | | [removed: [100](#i4188daee47a2424f9b9f03a13cf73aab_103)] [added: [96](#i4188daee47a2424f9b9f03a13cf73aab_103)] | | |

| [Management’s Report on Internal Control over Financial Reporting (Arizona Public Service Company)](#i4188daee47a2424f9b9f03a13cf73aab_109) | | | [removed: [101](#i4188daee47a2424f9b9f03a13cf73aab_109)] [added: [97](#i4188daee47a2424f9b9f03a13cf73aab_109)] | | |

| [Report of Independent Registered Public Accounting Firm](#i4188daee47a2424f9b9f03a13cf73aab_112) (PCAOB ID No. 34) | | | [removed: [102](#i4188daee47a2424f9b9f03a13cf73aab_112)] [added: [98](#i4188daee47a2424f9b9f03a13cf73aab_112)] | | |

| [APS Consolidated Statements of Income [removed: for 20](#i4188daee47a2424f9b9f03a13cf73aab_115)[24](#i4188daee47a2424f9b9f03a13cf73aab_115)[, 20](#i4188daee47a2424f9b9f03a13cf73aab_115)[23](#i4188daee47a2424f9b9f03a13cf73aab_115) [and 20](#i4188daee47a2424f9b9f03a13cf73aab_115)[22](#i4188daee47a2424f9b9f03a13cf73aab_115)] [added: for](#i4188daee47a2424f9b9f03a13cf73aab_115) [](#i4188daee47a2424f9b9f03a13cf73aab_115)[2025, 2024 and 2023](#i4188daee47a2424f9b9f03a13cf73aab_91)] | | | [removed: [106](#i4188daee47a2424f9b9f03a13cf73aab_115)] [added: [102](#i4188daee47a2424f9b9f03a13cf73aab_115)] | | |

| [APS Consolidated Statements of Comprehensive Income [removed: for 20](#i4188daee47a2424f9b9f03a13cf73aab_118)[24](#i4188daee47a2424f9b9f03a13cf73aab_118)[, 20](#i4188daee47a2424f9b9f03a13cf73aab_118)[23](#i4188daee47a2424f9b9f03a13cf73aab_118) [and 20](#i4188daee47a2424f9b9f03a13cf73aab_118)[22](#i4188daee47a2424f9b9f03a13cf73aab_118)] [added: for](#i4188daee47a2424f9b9f03a13cf73aab_118) [](#i4188daee47a2424f9b9f03a13cf73aab_118)[2025, 2024 and 2023](#i4188daee47a2424f9b9f03a13cf73aab_91)] | | | [removed: [107](#i4188daee47a2424f9b9f03a13cf73aab_118)] [added: [103](#i4188daee47a2424f9b9f03a13cf73aab_118)] | | |

| [APS Consolidated Balance Sheets as of December [removed: 31, 20](#i4188daee47a2424f9b9f03a13cf73aab_121)[24](#i4188daee47a2424f9b9f03a13cf73aab_121) [and 20](#i4188daee47a2424f9b9f03a13cf73aab_121)[23](#i4188daee47a2424f9b9f03a13cf73aab_121)] [added: 31,](#i4188daee47a2424f9b9f03a13cf73aab_121) [2025 and](#i4188daee47a2424f9b9f03a13cf73aab_121) [20](#i4188daee47a2424f9b9f03a13cf73aab_121)[24](#i4188daee47a2424f9b9f03a13cf73aab_121)] | | | [removed: [108](#i4188daee47a2424f9b9f03a13cf73aab_121)] [added: [104](#i4188daee47a2424f9b9f03a13cf73aab_121)] | | |

| [APS Consolidated Statements of Cash Flows [removed: for 20](#i4188daee47a2424f9b9f03a13cf73aab_124)[24](#i4188daee47a2424f9b9f03a13cf73aab_124)[, 20](#i4188daee47a2424f9b9f03a13cf73aab_124)[23](#i4188daee47a2424f9b9f03a13cf73aab_124) [and 20](#i4188daee47a2424f9b9f03a13cf73aab_124)[22](#i4188daee47a2424f9b9f03a13cf73aab_124)] [added: for](#i4188daee47a2424f9b9f03a13cf73aab_124) [2025, 2024 and 2023](#i4188daee47a2424f9b9f03a13cf73aab_91)] | | | [removed: [110](#i4188daee47a2424f9b9f03a13cf73aab_124)] [added: [106](#i4188daee47a2424f9b9f03a13cf73aab_124)] | | |

| [APS Consolidated Statements of Changes in Equity [removed: for 20](#i4188daee47a2424f9b9f03a13cf73aab_127)[24](#i4188daee47a2424f9b9f03a13cf73aab_127)[, 20](#i4188daee47a2424f9b9f03a13cf73aab_127)[23](#i4188daee47a2424f9b9f03a13cf73aab_127) [and 20](#i4188daee47a2424f9b9f03a13cf73aab_127)[22](#i4188daee47a2424f9b9f03a13cf73aab_127)] [added: for](#i4188daee47a2424f9b9f03a13cf73aab_127) [2025, 2024 and 2023](#i4188daee47a2424f9b9f03a13cf73aab_91)] | | | [removed: [111](#i4188daee47a2424f9b9f03a13cf73aab_127)] [added: [107](#i4188daee47a2424f9b9f03a13cf73aab_127)] | | |

| [Combined Notes to Consolidated Financial Statements](#i4188daee47a2424f9b9f03a13cf73aab_130) | | | [removed: [112](#i4188daee47a2424f9b9f03a13cf73aab_130)] [added: [108](#i4188daee47a2424f9b9f03a13cf73aab_130)] | | |

| [Note 1. Summary of Significant Accounting Policies](#i4188daee47a2424f9b9f03a13cf73aab_3230) | | | [removed: [112](#i4188daee47a2424f9b9f03a13cf73aab_3230)] [added: [108](#i4188daee47a2424f9b9f03a13cf73aab_3230)] | | |

| [removed: [Note 2.] [added: [Note](#i4188daee47a2424f9b9f03a13cf73aab_136) [4](#i4188daee47a2424f9b9f03a13cf73aab_136)[.] Revenue](#i4188daee47a2424f9b9f03a13cf73aab_136) | | | [removed: [122](#i4188daee47a2424f9b9f03a13cf73aab_136)] [added: [119](#i4188daee47a2424f9b9f03a13cf73aab_136)] | | |

| [removed: [Note 3.] [added: [Note](#i4188daee47a2424f9b9f03a13cf73aab_139) [8](#i4188daee47a2424f9b9f03a13cf73aab_139)[.] Regulatory Matters](#i4188daee47a2424f9b9f03a13cf73aab_139) | | | [removed: [123](#i4188daee47a2424f9b9f03a13cf73aab_139)] [added: [133](#i4188daee47a2424f9b9f03a13cf73aab_139)] | | |

| [removed: [Note 4.] [added: [Note](#i4188daee47a2424f9b9f03a13cf73aab_3309) [5](#i4188daee47a2424f9b9f03a13cf73aab_3309)[.] Income Taxes](#i4188daee47a2424f9b9f03a13cf73aab_3309) | | | [removed: [138](#i4188daee47a2424f9b9f03a13cf73aab_3309)] [added: [121](#i4188daee47a2424f9b9f03a13cf73aab_3309)] | | |

| [removed: [Note 5.] [added: [Note](#i4188daee47a2424f9b9f03a13cf73aab_3395) [6](#i4188daee47a2424f9b9f03a13cf73aab_3395)[.] Lines of Credit and Short-Term Borrowings](#i4188daee47a2424f9b9f03a13cf73aab_3395) | | | [removed: [143](#i4188daee47a2424f9b9f03a13cf73aab_3395)] [added: [128](#i4188daee47a2424f9b9f03a13cf73aab_3395)] | | |

| [removed: [Note 6.] [added: [Note](#i4188daee47a2424f9b9f03a13cf73aab_148) [7](#i4188daee47a2424f9b9f03a13cf73aab_148)[.] Long-Term Debt and Liquidity Matters](#i4188daee47a2424f9b9f03a13cf73aab_148) | | | [removed: [145](#i4188daee47a2424f9b9f03a13cf73aab_148)] [added: [130](#i4188daee47a2424f9b9f03a13cf73aab_148)] | | |

| [removed: [Note 7.] [added: [Note](#i4188daee47a2424f9b9f03a13cf73aab_151) [9](#i4188daee47a2424f9b9f03a13cf73aab_151)[.] Retirement Plans and Other Postretirement Benefits](#i4188daee47a2424f9b9f03a13cf73aab_151) | | | [removed: [150](#i4188daee47a2424f9b9f03a13cf73aab_151)] [added: [145](#i4188daee47a2424f9b9f03a13cf73aab_151)] | | |

| [removed: [Note 8.] [added: [Note](#i4188daee47a2424f9b9f03a13cf73aab_154) [20](#i4188daee47a2424f9b9f03a13cf73aab_154)[.] Leases](#i4188daee47a2424f9b9f03a13cf73aab_154) | | | [removed: [158](#i4188daee47a2424f9b9f03a13cf73aab_154)] [added: [189](#i4188daee47a2424f9b9f03a13cf73aab_154)] | | |

| [removed: [Note 9.] [added: [Note](#i4188daee47a2424f9b9f03a13cf73aab_157) [11](#i4188daee47a2424f9b9f03a13cf73aab_157)[.] Jointly-Owned Facilities](#i4188daee47a2424f9b9f03a13cf73aab_157) | | | [removed: [162](#i4188daee47a2424f9b9f03a13cf73aab_157)] [added: [157](#i4188daee47a2424f9b9f03a13cf73aab_157)] | | |

| [Note [removed: 10.] [added: 1](#i4188daee47a2424f9b9f03a13cf73aab_160)[4](#i4188daee47a2424f9b9f03a13cf73aab_160)[.] Commitments and Contingencies](#i4188daee47a2424f9b9f03a13cf73aab_160) | | | [removed: [163](#i4188daee47a2424f9b9f03a13cf73aab_160)] [added: [164](#i4188daee47a2424f9b9f03a13cf73aab_160)] | | |

| [removed: [Note 11.] [added: [Note](#i4188daee47a2424f9b9f03a13cf73aab_166) [2](#i4188daee47a2424f9b9f03a13cf73aab_166)[1.] Asset Retirement Obligations](#i4188daee47a2424f9b9f03a13cf73aab_166) | | | [removed: [172](#i4188daee47a2424f9b9f03a13cf73aab_166)] [added: [192](#i4188daee47a2424f9b9f03a13cf73aab_166)] | | |

| [Note [removed: 12.] [added: 1](#i4188daee47a2424f9b9f03a13cf73aab_3748)[7](#i4188daee47a2424f9b9f03a13cf73aab_3748)[.] Fair Value Measurements](#i4188daee47a2424f9b9f03a13cf73aab_3748) | | | [removed: [174](#i4188daee47a2424f9b9f03a13cf73aab_3748)] [added: [178](#i4188daee47a2424f9b9f03a13cf73aab_3748)] | | |

| [Note [removed: 13.] [added: 1](#i4188daee47a2424f9b9f03a13cf73aab_172)[6](#i4188daee47a2424f9b9f03a13cf73aab_172)[.] Common Stock Equity and Earnings Per Share](#i4188daee47a2424f9b9f03a13cf73aab_172) | | | [removed: [180](#i4188daee47a2424f9b9f03a13cf73aab_172)] [added: [175](#i4188daee47a2424f9b9f03a13cf73aab_172)] | | |

| [Note [removed: 14.] [added: 1](#i4188daee47a2424f9b9f03a13cf73aab_175)[0](#i4188daee47a2424f9b9f03a13cf73aab_175)[.] Stock-Based Compensation](#i4188daee47a2424f9b9f03a13cf73aab_175) | | | [removed: [182](#i4188daee47a2424f9b9f03a13cf73aab_175)] [added: [153](#i4188daee47a2424f9b9f03a13cf73aab_175)] | | |

| [Note [removed: 15.] [added: 1](#i4188daee47a2424f9b9f03a13cf73aab_178)[3](#i4188daee47a2424f9b9f03a13cf73aab_178)[.] Derivative Accounting](#i4188daee47a2424f9b9f03a13cf73aab_178) | | | [removed: [185](#i4188daee47a2424f9b9f03a13cf73aab_178)] [added: [160](#i4188daee47a2424f9b9f03a13cf73aab_178)] | | |

| [Note [removed: 16.] [added: 1](#i4188daee47a2424f9b9f03a13cf73aab_181)[5](#i4188daee47a2424f9b9f03a13cf73aab_181)[.] Other Income and Other Expense](#i4188daee47a2424f9b9f03a13cf73aab_181) | | | [removed: [189](#i4188daee47a2424f9b9f03a13cf73aab_181)] [added: [174](#i4188daee47a2424f9b9f03a13cf73aab_181)] | | |

| [Note [removed: 17.] [added: 1](#i4188daee47a2424f9b9f03a13cf73aab_187)[2](#i4188daee47a2424f9b9f03a13cf73aab_187)[.] Variable Interest Entities](#i4188daee47a2424f9b9f03a13cf73aab_187) | | | [removed: [190](#i4188daee47a2424f9b9f03a13cf73aab_187)] [added: [157](#i4188daee47a2424f9b9f03a13cf73aab_187)] | | |

| [Note 18. Investments in Nuclear Decommissioning Trusts and Other Special Use Funds](#i4188daee47a2424f9b9f03a13cf73aab_190) | | | [removed: [192](#i4188daee47a2424f9b9f03a13cf73aab_190)] [added: [185](#i4188daee47a2424f9b9f03a13cf73aab_190)] | | |

| [Note 19. Changes in Accumulated Other Comprehensive Loss](#i4188daee47a2424f9b9f03a13cf73aab_193) | | | [removed: [195](#i4188daee47a2424f9b9f03a13cf73aab_193)] [added: [188](#i4188daee47a2424f9b9f03a13cf73aab_193)] | | |

| [Note [removed: 20.] [added: 2](#i4188daee47a2424f9b9f03a13cf73aab_199)[2](#i4188daee47a2424f9b9f03a13cf73aab_199)[.] Sale of Bright Canyon Energy](#i4188daee47a2424f9b9f03a13cf73aab_199) | | | [removed: [196](#i4188daee47a2424f9b9f03a13cf73aab_199)] [added: [193](#i4188daee47a2424f9b9f03a13cf73aab_199)] | | |

| [removed: [Note 21.] [added: [Note](#i4188daee47a2424f9b9f03a13cf73aab_202) [3](#i4188daee47a2424f9b9f03a13cf73aab_202)[.] New Accounting Standards](#i4188daee47a2424f9b9f03a13cf73aab_202) | | | [removed: [197](#i4188daee47a2424f9b9f03a13cf73aab_202)] [added: [117](#i4188daee47a2424f9b9f03a13cf73aab_202)] | | |

Our management is responsible for establishing and maintaining adequate internal control over financial reporting, as such term is defined in Exchange Act [removed: Rules] [added: Rule] 13a-15(f), for Pinnacle West Capital Corporation.

Based on our evaluation under [removed: the framework in *Internal Control — Integrated Framework (2013),*] [added: this framework*,*] our management concluded that our internal control over financial reporting was effective as of December 31, [removed: 2024.][added: 2025.]

The effectiveness of our internal control over financial reporting as of December 31, [removed: 2024,] [added: 2025,] has been audited by Deloitte & Touche LLP, an independent registered public accounting firm, as stated in their report which is included herein and also relates to the Company’s consolidated financial statements.

We have audited the accompanying consolidated balance sheets of Pinnacle West Capital Corporation and subsidiaries (the “Company”) as of December 31, [removed: 2024] [added: 2025] and [removed: 2023,] [added: 2024,] the related consolidated statements of income, comprehensive income, changes in equity, and cash flows, for each of the three years in the period ended December 31, [removed: 2024,] [added: 2025,] and the related notes and the schedule listed in the Index at Item 15 (collectively referred to as the “financial statements”).

| [Note 2. Business Segments](#i4188daee47a2424f9b9f03a13cf73aab_5050) | | | [116](#i4188daee47a2424f9b9f03a13cf73aab_5050) | | |

| [Note 23. El Dorado Equity Investments](#i4188daee47a2424f9b9f03a13cf73aab_5261) | | | [194](#i4188daee47a2424f9b9f03a13cf73aab_5261) | | |

February 25, 2026

- For regulatory matters in process, we inspected APS’s filings with the ACC and the filings with the ACC by intervenors that may impact the APS’s future rates, for evidence that might contradict management’s assertions.

- We obtained an analysis from management and internal legal counsel regarding the probability of recovery for regulatory assets or refund or future reduction in rates for regulatory liabilities not yet addressed in a regulatory order to assess management’s assertion that amounts are probable of recovery or a future reduction in rates.

February 25, 2026

| | | | 2025 | | | | | | 2024 | | |

| | | | 2025 | | | | | | 2024 | | |

| Net income | | | $ | 631,643 | | | | | $ | 626,030 | | | | | $ | 518,781 | |

| Change in unrecognized tax benefits | | | 81,090 | | | | | | 75 | | | | | | 1,177 | | |

| Change in other long-term liabilities | | | 138,934 | | | | | | 24,719 | | | | | | 61,903 | | |

| Palo Verde sale leaseback noncontrolling interest acquisition | | | (198,744) | | | | | | — | | | | | | — | | |

| Net income | | | | | | | | | — | | | | | | | | | | | | — | | | | | | 616,531 | | | | | | — | | | | | | 15,112 | | | | | | 631,643 | | |

| Other comprehensive loss | | | | | | | | | — | | | | | | | | | | | | — | | | | | | — | | | | | | (1,466) | | | | | | — | | | | | | (1,466) | | |

| Issuance of common stock (b) | | | 1,807,057 | | | | | | 109,755 | | | | | | | | | | | | | | | | | | — | | | | | | — | | | | | | — | | | | | | 109,755 | | |

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

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

| Deconsolidation of noncontrolling interests (c) | | | | | | | | | — | | | | | | | | | | | | — | | | | | | — | | | | | | — | | | | | | (59,621) | | | | | | (59,621) | | |

| Balance, December 31, 2025 | | | 120,950,839 | | | | | | $ | 3,231,372 | | | | | (46,968) | | | | | | $ | (3,323) | | | | | $ | 3,850,817 | | | | | $ | (32,408) | | | | | $ | 40,617 | | | | | $ | 7,087,075 | |

(c) See Note 12 for information related to the Palo Verde sale leaseback purchases.

Based on our evaluation under this framework*,* our management concluded that our internal control over financial reporting was effective as of December 31, 2025.

February 25, 2026

We also have audited the Company’s internal control over financial reporting as of December 31, 2025, based on criteria established in Internal Control — Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission (COSO).

In our opinion, the financial statements referred to above present fairly, in all material respects, the financial position of the Company as of December 31, 2025 and 2024, and the results of its operations and its cash flows for each of the three years in the period ended December 31, 2025, in conformity with accounting principles generally accepted in the United States of America.

Also, in our opinion, the Company maintained, in all material respects, effective internal control over financial reporting as of December 31, 2025, based on criteria established in Internal Control — Integrated Framework (2013) issued by COSO.

Accounting for the economics of rate regulation impacts multiple financial statement line items and disclosures, such as property, plant and equipment; deferred fuel and purchased power regulatory asset; other regulatory assets; regulatory liabilities (short-term and long-term); operating revenues; fuel and purchased power expense; operations and maintenance expense; and depreciation and amortization expense.

Decisions to be made by the ACC in the future will impact the

We identified the impact of rate regulation as a critical audit matter due to the significant judgments made by management to support its assertions about impacted account balances and disclosures and the high degree of subjectivity involved in assessing the impact of future regulatory rate orders on the financial statements.

Our audit procedures related to the uncertainty of future decisions by the ACC included the following, among others:

We evaluated the external information and compared to management’s recorded regulatory assets and liabilities for completeness.

- For regulatory matters in process, we inspected the Company’s filings with the ACC and the filings with the regulatory authorities by intervenors that may impact the Company’s future rates, for evidence that might contradict managements assertions.

- We obtained an analysis from management and internal legal counsel regarding the probability of recovery for regulatory assets or refund or future reduction in rates for regulatory liabilities not yet addressed in a regulatory order to assess management’s assertion that amounts are probable of recovery or a future reduction in rates.

February 25, 2026

| OPERATING REVENUES (Note 4) | | | $ | 5,339,939 | | | | | $ | 5,124,915 | | | | | $ | 4,695,991 | |

| Fuel and purchased power | | | 1,933,420 | | | | | | 1,822,566 | | | | | | 1,792,657 | | |

| Other expense | | | 3,684 | | | | | | 2,389 | | | | | | 1,913 | | |

| Allowance for equity funds used during construction (Note 1) | | | 61,146 | | | | | | 38,620 | | | | | | 53,118 | | |

| Less: Net income attributable to noncontrolling interests (Note 12) | | | 15,112 | | | | | | 17,224 | | | | | | 17,224 | | |

| Less: Comprehensive income attributable to noncontrolling interests | | | 15,112 | | | | | | 17,224 | | | | | | 17,224 | | |

| | | | 2025 | | | | | | 2024 | | |

| | | | | | |

February 25, 2025

◦We read the ACC’s approved decision regarding the 2022 Retail Rate Case.

◦We obtained the Company’s internally prepared memo concluding on the impacts of the ACC’s approved decision regarding the 2022 Retail Rate Case on rates and recorded regulatory balances.

◦We read and analyzed the minutes of the Boards of Directors of the Company for discussions of changes in legal, regulatory, or business factors which could impact

management’s conclusions with respect to the financial statement impacts of rate regulation.

- We evaluated management’s assessment of the probability of recovery for regulatory assets or refund or future reduction in rates for regulatory liabilities based on applicable regulatory orders or precedents set by the ACC under similar circumstances.

We read the minutes of the Boards of Directors of the Company for discussions of changes in legal, regulatory, or business factors which could impact management’s assessment.

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

| Derivative instruments: | | | | | | | | | | | | | | | | | |

| Assets held for sale (Note 20) | | | — | | | | | | 35,139 | | |

| Change in other long-term liabilities | | | 24,794 | | | | | | 63,080 | | | | | | 170,359 | | |

| Balance, December 31, 2021 | | | 113,014,528 | | | | | | $ | 2,702,743 | | | | | (87,608) | | | | | | $ | (6,401) | | | | | $ | 3,264,719 | | | | | $ | (54,861) | | | | | $ | 115,260 | | | | | $ | 6,021,460 | |

| Net income | | | | | | | | | — | | | | | | | | | | | | — | | | | | | 483,602 | | | | | | — | | | | | | 17,224 | | | | | | 500,826 | | |

| Other comprehensive income | | | | | | | | | — | | | | | | | | | | | | — | | | | | | — | | | | | | 23,426 | | | | | | — | | | | | | 23,426 | | |

| Issuance of common stock | | | 232,661 | | | | | | 21,996 | | | | | | | | | | | | — | | | | | | — | | | | | | — | | | | | | — | | | | | | 21,996 | | |

| Purchase of treasury stock (a) | | | | | | | | | — | | | | | | (77,152) | | | | | | (5,152) | | | | | | — | | | | | | — | | | | | | — | | | | | | (5,152) | | |

| Reissuance of treasury stock for stock-based compensation and other | | | | | | | | | — | | | | | | 91,147 | | | | | | 6,548 | | | | | | — | | | | | | — | | | | | | — | | | | | | 6,548 | | |

As of December 31, 2024, 5,377,115 shares of common stock have been issued as part of these agreements.

| Change in other long-term liabilities | | | 27,202 | | | | | | 58,574 | | | | | | 168,503 | | |

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

| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |

| Balance, December 31, 2021 | | | 71,264,947 | | | | | | $ | 178,162 | | | | | $ | 3,021,696 | | | | | $ | 3,470,235 | | | | | $ | (34,880) | | | | | $ | 115,260 | | | | | $ | 6,750,473 | |

| Net income | | | | | | | | | — | | | | | | — | | | | | | 524,929 | | | | | | — | | | | | | 17,224 | | | | | | 542,153 | | |

| Other comprehensive income | | | | | | | | | — | | | | | | — | | | | | | — | | | | | | 19,284 | | | | | | — | | | | | | 19,284 | | |

BCE was a Pinnacle West subsidiary that was formed in 2014.

The sale was completed on January 12, 2024.

| Generation | | | $ | 11,111,915 | | | | | $ | 10,446,291 | |

the capitalized cost is depreciated over the useful life of the long-lived asset.

On June 30, 2020, FERC issued an order granting a waiver request related to the existing AFUDC rate calculation beginning March 1, 2020, through February 28, 2021.

On February 23, 2021, this waiver was extended until September 30, 2021.

On September 21, 2021, it was further extended until March 31, 2022.

The order provided a simplified approach that companies may elect to implement in order to minimize the significant distorted effect on the AFUDC formula resulting from increased short-term debt financing during the COVID-19 pandemic.

APS adopted this simplified approach to computing the AFUDC composite rate by using a simple average of the actual historical short-term debt balances for 2019, instead of current period short-term debt balances, and left all other aspects of the AFUDC formula composite rate calculation unchanged.

This change impacted the AFUDC composite rate in 2021 and for the three-month period ended March 31, 2022.

Furthermore, the change in the composite rate calculation did not impact our accounting treatment for these costs.

See Note 7 for additional information on pension and other postretirement benefits.

See Note 10 for information on spent nuclear fuel disposal costs.

See Note 8 for information on our lease agreements.

| Other income and expenses, net (a) | | | 28 | | | 22 | | | 50 | | | | | | 60 | | | — | | | 60 | | | | | | 22 | | | (23) | | | (1) | | |

Pinnacle West’s management, with the participation of Pinnacle West’s Chief Executive Officer and Chief Financial Officer, have evaluated the effectiveness of Pinnacle West’s disclosure controls and procedures as of December 31, [removed: 2024.][added: 2025.]

APS’s management, with the participation of APS’s Chief Executive Officer and Chief Financial Officer, have evaluated the effectiveness of APS’s disclosure controls and procedures as of December 31, [removed: 2024.][added: 2025.]

No change in Pinnacle West’s or APS’s internal control over financial reporting occurred during the fiscal quarter ended December 31, [removed: 2024,] [added: 2025,] that materially affected, or is reasonably likely to materially affect, Pinnacle West’s or APS’s internal control over financial reporting.

During the [removed: fiscal quarter] [added: year] ended December 31, [removed: 2024,] [added: 2025,] none of our directors or executive officers adopted or terminated any contract, instruction or written plan for the purchase or sale of our securities to satisfy the affirmative defense conditions of Rule 10b5-1(c) or any “non-Rule 10b5-1 trading arrangement.”

AND CORPORATE [removed: GOVERNANCE OF PINNACLE WEST][added: GOVERNANCE]

Reference is hereby made to “Information About Our Board and Corporate Governance” and “Proposal 1 — Election of Directors” in the Pinnacle West Proxy Statement relating to the Annual Meeting of Shareholders to be held on May [removed: 21, 2025] [added: 14, 2026] (the [removed: “2025] [added: “2026] Proxy Statement”) and to the “Information about our Executive Officers” section in Part I of this report.

Reference is hereby made to “Director Compensation,” “Executive Compensation,” and “Human Resources Committee Interlocks and Insider Participation” in the [removed: 2025] [added: 2026] Proxy Statement.

Reference is hereby made to “Ownership of Pinnacle West Stock” in the [removed: 2025] [added: 2026] Proxy Statement.

The following table sets forth information as of December 31, [removed: 2024,] [added: 2025,] with respect to the 2021 Plan, 2012 Plan, the 2007 Plan, under which our equity securities are outstanding or currently authorized for issuance.

| Equity compensation plans approved by security holders | | | [removed: 1,632,699] [added: 1,624,697] | | | | | | — | | | | | | [removed: 2,941,625] [added: 2,477,607] | | |

Additional shares cannot be awarded under the 2012 Plan, as amended, [removed: and] [added: or] the 2007 Plan.

See Note [removed: 14] [added: 10] of the Notes to Consolidated Financial Statements for additional information regarding these plans.

| Total | | | 1,624,697 | | | | | | — | | | | | | 2,477,607 | | |

| Total | | | 1,632,699 | | | | | | — | | | | | | 2,941,625 | | |

Reference is hereby made to “Information About Our Board and Corporate Governance” and “Related Party Transactions” in the [removed: 2025] [added: 2026] Proxy Statement.

Reference is hereby made to “Audit Matters — Audit Fees and — Pre-Approval Policies” in the [removed: 2025] [added: 2026] Proxy Statement.

| Type of Service | | | | | | [removed: 2024] [added: 2025] | | | | | | [removed: 2023] [added: 2024] | | |

| Audit Fees (1) | | | | | | $ | [removed: 2,967,862] [added: 2,971,594] | | | | | $ | [removed: 2,707,633] [added: 2,967,862] | |

| Audit-Related Fees (2) | | | | | | [removed: 384,372] [added: 403,620] | | | | | | [removed: 372,040] [added: 384,372] | | |

(2) The aggregate fees billed for assurance and related services that are reasonably related to the performance of the audit or review of the financial statements and are not included in Audit Fees reported above, which primarily consist of fees for employee benefit plan audits in [removed: 2023] [added: 2025] and 2024.

[removed: Pinnacle West’s] [added: The] Audit Committee pre-approves each audit service and non-audit service to be provided by [removed: APS’s registered public accounting firm.][added: Deloitte and Touche LLP for APS.]

All of the services performed by Deloitte & Touche LLP for APS in [removed: 2024] [added: 2025] were pre-approved by the Audit Committee or the Chair consistent with the pre-approval policy.

| All Other Fees (3) | | | | | | — | | | | | | 1,672,676 | | |

(3) The aggregate fees billed for independent third-party advisory (quality assurance) services related to a large-scale information technology project.

| Exhibit No. | | | | | | Registrant(s) | | | | | | Description | | | | | | Previously Filed as [removed: Exhibit: a] [added: Exhibit:] | | | | | | Date Filed | | |

| 3.1 | | | | | | Pinnacle West | | | | | | [Articles of Incorporation, restated as of May [removed: 21, 2008](https://www.sec.gov/Archives/edgar/data/7286/000095015308001386/p76062exv3w1.htm)] [added: 22, 2025](https://www.sec.gov/Archives/edgar/data/7286/000076462225000072/exhibit31.htm)] | | | | | | 3.1 to Pinnacle West/APS June 30, [removed: 2008] [added: 2025] Form 10-Q [removed: Report, File No. 1-8962] [added: Report] | | | | | | [removed: 8/7/2008] [added: 8/6/2025] | | |

| 3.2 | | | | | | Pinnacle West | | | | | | [Pinnacle West Capital Corporation Bylaws, amended as of February 19, 2020](https://www.sec.gov/Archives/edgar/data/7286/000076462220000022/a8-k021920exhibit31.htm) | | | | | | 3.1 to Pinnacle West/APS February 25, 2020 Form 8-K [removed: Report, File Nos. 1-8962 and 1-4473] [added: Report] | | | | | | 2/25/2020 | | |

| [removed: 3.3(1)] [added: 3.3] | | | | | | APS | | | | | | [removed: [Amendment to the] [added: [APS] Articles of [removed: Incorporation] [added: Incorporation, restated as] of [removed: Arizona Public Service Company, amended] May 16, [removed: 2012](https://www.sec.gov/Archives/edgar/data/7286/000110465912039100/a12-12612_1ex3d1.htm)] [added: 2012](https://www.sec.gov/Archives/edgar/data/7286/000076462225000072/exhibit33.htm)] | | | | | | [removed: 3.1] [added: 3.3] to Pinnacle West/APS [removed: May 22, 2012] [added: June 30, 2025] Form [removed: 8-K Report, File Nos. 1-8962 and 1-4473] [added: 10-Q Report] | | | | | | [removed: 5/22/2012] [added: 8/6/1993] | | |

| 3.4 | | | | | | APS | | | | | | [removed: [Arizona Public Service Company Bylaws,] [added: [APS](https://www.sec.gov/Archives/edgar/data/7286/000095013409003359/p14106exv3w4.htm) [](https://www.sec.gov/Archives/edgar/data/7286/000095013409003359/p14106exv3w4.htm)[Bylaws,] amended as of December 16, 2008](https://www.sec.gov/Archives/edgar/data/7286/000095013409003359/p14106exv3w4.htm) | | | | | | 3.4 to Pinnacle West/APS [removed: December 31,] 2008 Form 10-K [removed: Report, File No. 1-4473] [added: Report] | | | | | | 2/20/2009 | | |

| 4.1 | | | | | | Pinnacle West | | | | | | [Specimen Certificate of Pinnacle West Capital Corporation Common Stock, no par value](https://www.sec.gov/Archives/edgar/data/764622/000076462217000044/a8kstockcertificatespeci.htm) | | | | | | 4.1 to Pinnacle West June 20, 2017 Form 8-K [removed: Report, File No. 1-8962] [added: Report] | | | | | | 6/20/2017 | | |

| [removed: 4.2] [added: 4.3] | | | | | | Pinnacle West APS | | | | | | [Indenture dated as of January [removed: 1, 1995 among] [added: 15, 1998 between] APS and The Bank of New York [removed: Mellon,] [added: Mellon Trust Company N.A. (successor to JPMorgan Chase Bank, N.A., formerly known] as [removed: Trustee](https://www.sec.gov/Archives/edgar/data/7286/0000950147-95-000002.txt)] [added: The Chase Manhattan Bank), as Trustee](https://www.sec.gov/Archives/edgar/data/7286/0000950147-98-000031.txt)] | | | | | | [removed: 4.6] [added: 4.10] to APS’s Registration Statement Nos. [removed: 33-61228] [added: 333-15379] and [removed: 33-55473] [added: 333-27551] by means of [added: APS] January [removed: 1, 1995] [added: 13, 1998] Form 8-K [removed: Report, File No. 1-4473] [added: Report] | | | | | | [removed: 1/11/1995] [added: 1/16/1998] | | |

| [removed: 4.3] [added: 4.3(b)] | | | | | | Pinnacle West APS | | | | | | [removed: [Indenture] [added: [Ninth Supplemental Indenture] dated as of [removed: November] [added: August] 15, [removed: 1996 between APS and The Bank of New York, as Trustee](https://www.sec.gov/Archives/edgar/data/7286/0000950147-96-000580.txt)] [added: 2005](https://www.sec.gov/Archives/edgar/data/7286/000095015305002105/p71111exv4w1.htm)] | | | | | | [removed: 4.5] [added: 4.1] to APS’s Registration Statements Nos. [removed: 33-61228, 33-55473, 33-64455] [added: 333-106772] and [removed: 333-15379] [added: 333-121512] by means of [removed: November 19, 1996] [added: APS August 17, 2005] Form 8-K [removed: Report, File No. 1-4473] [added: Report] | | | | | | [removed: 11/22/1996] [added: 8/22/2005] | | |

| [removed: 4.4] [added: 4.2] | | | | | | Pinnacle West | | | | | | [Indenture dated as of December 1, 2000 between the Company and The Bank of New York, as Trustee, relating to Senior Unsecured Debt Securities](https://www.sec.gov/Archives/edgar/data/764622/000095014700500305/ex4_1.txt) | | | | | | 4.1 to Pinnacle West’s Registration Statement No. 333-52476 | | | | | | 12/21/2000 | | |

| [removed: 4.4(a)] [added: 4.2(a)] | | | | | | Pinnacle West | | | | | | [removed: [Fourth] [added: [F](https://www.sec.gov/Archives/edgar/data/764622/000110465924070030/tm2413531d7_ex4-1.htm)[ifth] Supplemental Indenture [removed: dated as] [added: dated](https://www.sec.gov/Archives/edgar/data/764622/000110465924070030/tm2413531d7_ex4-1.htm) [as] of [removed: June 17, 2020](https://www.sec.gov/Archives/edgar/data/764622/000076462220000049/exhibit41fourthsupplem.htm)] [added: June](https://www.sec.gov/Archives/edgar/data/764622/000110465924070030/tm2413531d7_ex4-1.htm) [10](https://www.sec.gov/Archives/edgar/data/764622/000110465924070030/tm2413531d7_ex4-1.htm)[, 2024](https://www.sec.gov/Archives/edgar/data/764622/000110465924070030/tm2413531d7_ex4-1.htm)] | | | | | | 4.1 to Pinnacle West June [removed: 10, 2020] [added: 5, 2024] Form 8-K [removed: Report, File No. 1-8962] [added: Report] | | | | | | [removed: 6/16/2020] [added: 6/10/2024] | | |

| [removed: 4.4(b)] [added: 4.2(b)] | | | | | | Pinnacle West | | | | | | [removed: [F](https://www.sec.gov/Archives/edgar/data/764622/000110465924070030/tm2413531d7_ex4-1.htm)[ifth] [added: [Sixth] Supplemental Indenture [removed: dated](https://www.sec.gov/Archives/edgar/data/764622/000110465924070030/tm2413531d7_ex4-1.htm) [as] [added: dated as] of [removed: June](https://www.sec.gov/Archives/edgar/data/764622/000110465924070030/tm2413531d7_ex4-1.htm) [10](https://www.sec.gov/Archives/edgar/data/764622/000110465924070030/tm2413531d7_ex4-1.htm)[, 2024](https://www.sec.gov/Archives/edgar/data/764622/000110465924070030/tm2413531d7_ex4-1.htm)] [added: May 15, 2025](https://www.sec.gov/Archives/edgar/data/764622/000110465925049467/tm2513558d4_ex4-1.htm)] | | | | | | 4.1 to Pinnacle West [removed: June 5, 2024] [added: May 15, 2025] Form 8-K [removed: Report, File No. 1-8962] [added: Report] | | | | | | [removed: 6/10/2024] [added: 5/15/2025] | | |

| [removed: 4.5] [added: 4.6] | | | | | | Pinnacle West | | | | | | [removed: [Indenture] [added: [Indenture,] dated as of [removed: December 1, 2000] [added: June 6, 2024,] between the Company and The Bank of New [removed: York,] [added: York Mellon Trust Company, N.A.,] as [removed: Trustee, relating to Subordinated Unsecured Debt Securities](https://www.sec.gov/Archives/edgar/data/764622/000095014700500305/ex4_2.txt)] [added: trustee](https://www.sec.gov/Archives/edgar/data/764622/000110465924069111/tm2413531d6_ex4-1.htm)] | | | | | | [removed: 4.2] [added: 4.1] to Pinnacle [removed: West’s Registration Statement No. 333-52476] [added: West June 6, 2024 Form 8-K Report] | | | | | | [removed: 12/21/2000] [added: 6/6/2024] | | |

| [removed: 4.6(a)] [added: 4.3(a)] | | | | | | Pinnacle West APS | | | | | | [Seventh Supplemental Indenture dated as of May 1, 2003](https://www.sec.gov/Archives/edgar/data/7286/000095014703000593/ex4-1.txt) | | | | | | 4.1 to APS’s Registration Statement No. 333-90824 by means of [added: APS] May 7, 2003 Form 8-K [removed: Report, File No. 1-4473] [added: Report] | | | | | | 5/9/2003 | | |

| [removed: 4.6(b)] [added: 4.3(q)] | | | | | | Pinnacle West APS | | | | | | [removed: [Ninth] [added: [Twenty-Eighth] Supplemental Indenture dated as of August [removed: 15, 2005](https://www.sec.gov/Archives/edgar/data/7286/000095015305002105/p71111exv4w1.htm)] [added: 16, 2021](https://www.sec.gov/Archives/edgar/data/7286/000076462221000056/exhibit4108162128thsupplem.htm)] | | | | | | 4.1 to [removed: APS’s Registration Statements Nos. 333-106772 and 333-121512 by means of] [added: Pinnacle West/APS] August [removed: 17, 2005] [added: 16, 2021] Form 8-K [removed: Report, File No. 1-4473] [added: Report] | | | | | | [removed: 8/22/2005] [added: 8/16/2021] | | |

| [removed: 4.6(c)] [added: 4.3(c)] | | | | | | APS | | | | | | [Tenth Supplemental Indenture dated as of August 1, 2006](https://www.sec.gov/Archives/edgar/data/7286/000095015306002013/p72693exv4w1.htm) | | | | | | 4.1 to [removed: APS’s] [added: APS] July 31, 2006 Form 8-K [removed: Report, File No. 1-4473] [added: Report] | | | | | | 8/3/2006 | | |

| [removed: 4.6(d)] [added: 4.3(d)] | | | | | | Pinnacle West APS | | | | | | [Twelfth Supplemental Indenture dated as of August 25, 2011](https://www.sec.gov/Archives/edgar/data/7286/000076462215000013/exhibit46f.htm) | | | | | | 4.6f to Pinnacle West/APS 2014 Form 10-K [removed: Report, File Nos. 1-8962 and 1-4473] [added: Report] | | | | | | 2/20/2015 | | |

| [removed: 4.6(e)] [added: 4.3(e)] | | | | | | Pinnacle West APS | | | | | | [Thirteenth Supplemental Indenture dated as of January 13, 2012](https://www.sec.gov/Archives/edgar/data/7286/000076462215000013/exhibit46g.htm) | | | | | | 4.6g to Pinnacle West/APS 2014 Form 10-K [removed: Report, File Nos. 1-8962 and 1-4473] [added: Report] | | | | | | 2/20/2015 | | |

| [removed: 4.6(f)] [added: 4.3(f)] | | | | | | Pinnacle West APS | | | | | | [Fourteenth Supplemental Indenture dated as of January 10, 2014](https://www.sec.gov/Archives/edgar/data/7286/000076462215000013/exhibit46h.htm) | | | | | | 4.6h to Pinnacle West/APS 2014 Form 10-K [removed: Report, File Nos. 1-8962 and 1-4473] [added: Report] | | | | | | 2/20/2015 | | |

| [removed: 4.6(g)] [added: 4.3(g)] | | | | | | Pinnacle West APS | | | | | | [removed: [Seventeenth] [added: [Eighteenth] Supplemental Indenture dated as of [removed: May 19, 2015](https://www.sec.gov/Archives/edgar/data/7286/000076462215000033/exhibit41seventeenthsupple.htm)] [added: November 6, 2015](https://www.sec.gov/Archives/edgar/data/7286/000076462215000073/exhibit41eighteenthsupplem.htm)] | | | | | | 4.1 to Pinnacle West/APS [removed: May 14,] [added: November 3,] 2015 Form 8-K [removed: Report, File Nos. 1-8962 and 1-4473] [added: Report] | | | | | | [removed: 5/19/2015] [added: 11/6/2015] | | |

| [removed: 4.6(h)] [added: 4.3(n)] | | | | | | Pinnacle West APS | | | | | | [removed: [Eighteenth] [added: [Twenty-Fifth] Supplemental Indenture dated as of November [removed: 6, 2015](https://www.sec.gov/Archives/edgar/data/7286/000076462215000073/exhibit41eighteenthsupplem.htm)] [added: 20, 2019](https://www.sec.gov/Archives/edgar/data/7286/000076462219000100/exhibit41twenty-fifths.htm)] | | | | | | 4.1 to Pinnacle West/APS November [removed: 3, 2015] [added: 20, 2019] Form 8-K [removed: Report, File Nos. 1-8962 and 1-4473] [added: Report] | | | | | | [removed: 11/6/2015] [added: 11/20/2019] | | |

| [removed: 4.6(i)] [added: 4.3(h)] | | | | | | Pinnacle West APS | | | | | | [Nineteenth Supplemental Indenture dated as of May 6, 2016](https://www.sec.gov/Archives/edgar/data/7286/000110465916118564/a16-9669_3ex4d1.htm) | | | | | | 4.1 to Pinnacle West/APS May 3, 2016 Form 8-K [removed: Report, File Nos. 1-8962 and 1-4473] [added: Report] | | | | | | 5/6/2016 | | |