HA Sustainable Infrastructure Capital, Inc.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 10-K

For the fiscal year ended December 31, 2025

OR

For the transition period from to

Commission File Number:001-35877

(Exact name of registrant as specified in its charter)

(410)571-9860

(Registrant’s telephone number, including area code)

Securities registered pursuant to Section 12(b) of the Act:

Securities registered pursuant to Section 12(g) of the Act:

None

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Yes ☒ No☐

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Exchange Act. Yes☐ No ☒

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes ☒ No☐

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§ 232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files). Yes ☒ No☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer”, “accelerated filer,” “smaller reporting company” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.☐

Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internal controls over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report.☒

If securities are registered pursuant to Section 12(b) of the Act, indicate by check mark whether the financial statements of the registrant included in the filing reflect the correction of an error to previously issued financial statements.☐

Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of incentive-based compensation received by any of the registrant’s executive officers during the relevant recovery period pursuant to §240.10D-1(b).☐

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes☐ No☒

As of June 30, 2025, the aggregate market value of the registrant’s common stock (includes unvested restricted stock) held by non-affiliates of the registrant was $3.3 billion based on the closing sales price of the registrant’s common stock on June 30, 2025 as reported on the New York Stock Exchange.

On February 9, 2026, the registrant had a total of 128,184,572 shares of common stock, $0.01 par value, outstanding (which includes 463,952 shares of unvested restricted common stock).

DOCUMENTS INCORPORATED BY REFERENCE

Portions of the registrant’s proxy statement for the 2026 annual meeting of stockholders are incorporated by reference into Part III of this Annual Report on Form 10-K.

TABLE OF CONTENTS

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FORWARD-LOOKING STATEMENTS

We make forward-looking statements in this Annual Report on Form 10-K (“Form 10-K”) within the meaning of Section 27A of the Securities Act of 1933, as amended (the “Securities Act”), and Section 21E of the Securities Exchange Act of 1934, as amended (the “Exchange Act”) that are subject to risks and uncertainties. For these statements, we claim the protections of the safe harbor for forward-looking statements contained in such Sections. These forward-looking statements include information about possible or assumed future results of our business, financial condition, liquidity, results of operations, plans and objectives. When we use the words “believe,” “expect,” “anticipate,” “estimate,” “plan,” “continue,” “intend,” “should,” “may” or similar expressions, we intend to identify forward-looking statements. However, the absence of these words or similar expressions does not mean that a statement is not forward-looking. All statements that address operating performance, events or developments that we expect or anticipate will occur in the future are forward-looking statements.

Forward-looking statements are subject to significant risks and uncertainties. Investors are cautioned against placing undue reliance on such statements. Actual results may differ materially from those set forth in the forward-looking statements. Accordingly, any such statements are qualified in their entirety by reference to, and are accompanied by, important factors included in Part I, Item 1A. Risk Factors (in addition to any assumptions and other factors referred to specifically in connection with such forward-looking statements) that could have a significant impact on our operations and financial results, and could cause our actual results to differ materially from those contained or implied in forward-looking statements made by or on our behalf in this Form 10-K, in presentations, on our websites, in response to questions or otherwise.

Any forward-looking statement speaks only as of the date on which such statement is made, and we undertake no obligation to update any forward-looking statement to reflect events or circumstances, including, but not limited to, unanticipated events, after the date on which such statement is made, unless otherwise required by law. New factors emerge from time to time and it is not possible for management to predict all of such factors, nor can it assess the impact of each such factor on the business or the extent to which any factor, or combination of factors, may cause actual results to differ materially from those contained or implied in any forward-looking statement.

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RISK FACTOR SUMMARY

An investment in our securities involves risk. You should carefully consider the risks summarized in Item 1A, “Risk Factors” included in this report. These risks include, but are not limited to, the following:

Risks Related to Our Business and Our Industry

•If the market for various types of climate solutions projects or the investment techniques related to such projects do not develop as we anticipate, new business generation in this target area may be adversely impacted.

•We are subject to risks related to our sustainability and governance activities and disclosures.

•We operate in a competitive market, which may impact the terms of the investments we make.

•Our business is influenced by and depends in part on U.S. federal, state and local government laws, regulations and policies, and changes in such laws, regulations or policies, or a decline in the level of government support could adversely affect our business.

Risks Related to Our Assets and Projects in Which We Invest

•Changes in interest rates could adversely affect the value of our assets and negatively affect our profitability.

•The lack of liquidity of our assets may adversely affect our business, including our ability to value our assets.

•The preparation of our financial statements, including provision for loan losses, involves use of estimates, judgments and assumptions, and our financial statements may be materially affected if our estimates prove to be incorrect.

•We rely on our project sponsors for financial reporting related to our project companies, and our financial statements may be materially affected if the financial reporting related to our project companies proves to be incorrect.

•Our investments are subject to delinquency, foreclosure and loss, any or all of which could result in losses to us.

•Our subordinated and mezzanine debt and equity investments, many of which are illiquid with no readily available market, involve a degree of risk.

•We either do not control or jointly control the projects in which we invest, which may result in the project owner making certain business decisions or taking risks with which we disagree.

•Many of our assets depend on revenues from third-party contractual arrangements, including PPAs, that expose the projects to various risks.

•Portions of the electricity our assets generate is sold on the open market at spot-market prices. A prolonged environment of prices for natural gas, or other conventional fuel sources, below the levels at which we assumed when underwriting these investments, may have a material adverse effect on our long-term business prospects, financial condition and results of operations.

•Some of the projects in which we invest may require substantial operating or capital expenditures in the future.

•We invest in projects which rely on third parties to manufacture quality products or provide reliable services in a timely manner and the failure of these third parties could cause project performance to be adversely affected.

•Our insurance and contractual protections may not always cover lost revenue, increased expenses or liquidated damages payments.

•Energy efficiency, renewable energy and other sustainable infrastructure projects are subject to performance risks, including risks due to extreme weather events, that could impact the repayment of and the return on our assets.

Risks Related to Our Company and Structure

•Our management and employees depend on information systems and system failures could significantly disrupt our business, which may, in turn, negatively affect the market price of our common stock and our ability to pay dividends to our stockholders.

•Our qualification as a REIT for prior taxable years depends on interpretation of highly technical and complex legal provisions, and our failure to qualify as a REIT for prior taxable years would subject us to U.S. federal income tax and potentially state and local tax.

•Our ability to utilize our NOLs and other carryforwards may be limited.

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Risks Relating to Regulation

•We cannot predict the unintended consequences and market distortions that may stem from far-ranging governmental intervention in the economic and financial system or from regulatory reform of the oversight of financial markets.

•Loss of our 1940 Act exemptions may adversely affect us, the market price of shares of our common stock and our ability to distribute dividends.

Risks Related to our Borrowings and Hedging

•We and our subsidiaries may be able to incur substantially more indebtedness, which may increase the risks to our financial condition and results of operations created by our indebtedness.

•An increase in our borrowing costs relative to the interest we receive on our assets may adversely affect our profitability and our cash available for distribution to our stockholders. Our borrowings may have a shorter duration than our assets.

•While we have an established Board-approved leverage limit, our Board of Directors (our “Board”) may change our financial leverage guidelines without stockholder consent.

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