425

425 1 d47568d425.htm 425 425

Filed by Public Storage

(Commission File No.: 001-33519)

Pursuant to Rule 425 under the Securities Act of 1933, as amended

and deemed filed pursuant to Rule 14a-12

under the Securities Exchange Act of 1934

Subject Company: National Storage Affiliates Trust

(Commission File No.: 001-37351)

Date: March 16, 2026

The following email was sent on behalf of H. Thomas Boyle, Public Storage’s current Chief Investment Officer and incoming Chief Executive Officer, to Public Storage’s corporate employees on March 16, 2026.

To: Corporate Employees

Subject: PS 4.0 Milestone: Public Storage Announces Acquisition of NSA Storage

LOGO

Sent on behalf of Tom Boyle, Incoming Chief Executive Officer

Public Storage Team,

A few weeks ago, we shared our vision for the next transformational era of Public Storage, PS4.0. This strategic vision is all about growth – reinforcing our industry leadership and aggressively capitalizing on opportunities to strengthen our portfolio, team, and capabilities.

Today, we are announcing our first value creation milestone in line with this vision: Public Storage has reached an agreement to acquire NSA Storage. Being the best in the industry means we don’t sit and wait for opportunities: we capitalize on them when they create value for our business and our team.

This is a rare available opportunity to acquire a large-scale, diversified portfolio. NSA brings more than 1,000 locations and 550,000 units across 38 states. Together, our nation-wide platform will include nearly 4,600 locations and 330 million net rentable square feet. With NSA’s strong presence in the Sun Belt, we will expand our leadership in key growth markets. This major acquisition will showcase the benefits of our next-generation operating model, PS Next. By applying our best-in-class operating practices to NSA’s properties, we are confident in our ability to enhance their financial profile and create greater value for all stakeholders. Our work will truly be an example of “stronger together”: enabling us to serve NSA’s more than 500,000 customers with better capabilities and economics. NSA customers will benefit from our AI-led offerings and digital customer ecosystem, enhancing the service and experience they receive across the platform.

With the continued growth of our platform, we look forward to offering new career development opportunities for our people as part of a larger, more diversified organization. We will share more in the coming weeks and months about our comprehensive integration process and the growth opportunities this will create for team members.

We expect the transaction to close in the second half of 2026. NSA’s leadership has built a strong platform with great properties, and we are confident their talented team will be an excellent cultural fit and look forward to welcoming them to Public Storage.

You can read more details in the press release we issued announcing the transaction. And if you have any questions, please reach out to your manager.

I want to thank the entire team for the tremendous work you do to put Public Storage in a position of strength. This transaction underscores our status as the industry’s partner of choice, with an unparalleled track record of financial performance and shareholder value creation.

I look forward to even more growth and success together!

LOGO

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Cautionary Statement Regarding Forward-Looking Statements

This communication contains “forward-looking statements” within the meaning of Section 27A of the Securities Act of 1933, as amended (the “Securities Act”), and in Section 21E of the Securities Exchange Act of 1934, as amended, which are based on current expectations, estimates and projections about the industry and markets in which National Storage Affiliates Trust (“NSA”) and Public Storage operate, as well as beliefs and assumptions of NSA and Public Storage. Words such as “anticipate,” “become,” “believe,” “could,” “estimate,” “expect,” “forecast,” “intend,” “may,” “outlook,” “plan,” “potential,” “possible,” “predict,” “project,” “target,” “seek,” “shall,” “should,” “will,” or “would,” including variations of such words and similar expressions, are intended to identify forward-looking statements. All statements that address operating performance, events or developments that NSA or Public Storage expects or anticipates will occur in the future are forward-looking statements, including statements relating to any possible transaction between NSA and Public Storage, rent and occupancy growth, acquisition and development activity, acquisition and disposition activity, general conditions in the geographic areas where NSA and Public Storage operate, NSA’s and Public Storage’s respective debt, capital structure and financial position and NSA’s and Public Storage’s respective ability to form new ventures. Such forward-looking statements are not guarantees of future performance and involve known and unknown risks, uncertainties, assumptions and other factors that are difficult to predict and may cause the actual results to differ materially from future results expressed or implied by such forward-looking statements.

Important factors, risks and uncertainties that could cause actual results to differ materially from such plans, estimates or expectations include but are not limited to: (i) the parties’ ability to complete the proposed transaction on the proposed terms or on the anticipated timeline, or at all, including risks and uncertainties related to NSA’s ability to obtain the required shareholder and unitholder approval, and the parties’ ability to satisfy the other conditions to consummating the proposed transaction; (ii) the inability to realize the anticipated benefits of the proposed transaction, including as a result of delay in completing the proposed transaction; (iii) the risk that NSA’s business will not be integrated successfully with Public Storage’s or that such integration may be more difficult, time-consuming or costly than expected; (iv) significant transaction costs and/or unknown or inestimable liabilities; (v) potential litigation relating to the proposed transaction that could be instituted against NSA or its trustees, managers or officers, including resulting expense or delay and the effects of any outcomes related thereto; (vi) the risk that disruptions from the proposed transaction, including diverting the attention of NSA and Public Storage management from ongoing business operations, will harm NSA’s and Public Storage’s businesses during the pendency of the proposed transaction or otherwise; (vii) certain restrictions during the pendency of the business combination that may impact NSA’s and Public Storage’s ability to pursue certain business opportunities or strategic transactions; (viii) the possibility that the business combination may be more expensive to complete than anticipated, including as a result of unexpected factors or events; (ix) the occurrence of any event, change or other circumstance that could give rise to the termination of the merger agreement, including in circumstances requiring NSA to pay a termination fee; (x) the effect of the announcement of the proposed transaction on the ability of NSA and Public Storage to operate their respective businesses and retain and hire key personnel, and to maintain favorable business relationships; (xi) risks related to the market value of Public Storage common stock to be issued in the proposed transaction; (xii) other risks related to the completion of the proposed transaction and actions related thereto; (xiii) potential business uncertainty, including changes to existing business relationships, during the pendency of the business combination or otherwise that could affect NSA’s or Public Storage’s financial performance; (xiv) other risks related to the completion of the proposed transaction and actions related thereto; (xv) legislative, regulatory and economic developments; (xvi) unpredictability and severity of local, regional, national and international economic, political and catastrophic climates, conditions and events, including but not limited to acts of terrorism, outbreaks of war or hostilities or pandemics, as well as management’s response to any of the aforementioned factors; (xvii) changes in global financial markets, interest rates and foreign currency exchange rates; (xviii) increased or unanticipated competition affecting NSA’s or Public Storage’s properties; (xix) risks associated with acquisitions, dispositions and development of properties, including increased development costs due to additional regulatory requirements related to climate change; (xx) maintenance of Real Estate Investment Trust status, tax structuring and changes in income tax laws and rates; (xxi) risks related to NSA’s and Public Storage’s investments in ventures, including NSA’s and Public Storage’s respective abilities to establish new ventures; (xxii) environmental uncertainties, including risks of natural disasters; (xxiii) those risks and uncertainties set forth in NSA’s and Public Storage’s Annual Reports on Form 10-K for the year ended December 31, 2025 under the headings “Forward-Looking Statements” and “Cautionary Statement Regarding Forward-Looking Statements,” respectively, and “Risk Factors,” as such risk factors may be amended, supplemented or superseded from time to time by other reports filed by NSA or Public Storage, as the case may be, with the Securities and Exchange Commission (the “SEC”) from time to

time, which are available via the SEC’s website at www.sec.gov; and (xxiv) those risks that will be described in the Registration Statement and Proxy Statement/Prospectus that will be filed with the SEC in connection with the proposed transaction and available from the sources indicated below. There can be no assurance that the proposed transaction will be completed, or if it is completed, that it will close within the anticipated time period. These factors should not be construed as exhaustive and should be read in conjunction with the other forward-looking statements. Forward-looking statements relate only to events as of the date on which the statements are made. Neither NSA nor Public Storage undertakes any obligation to publicly update or review any forward-looking statement except as required by law, whether as a result of new information, future developments or otherwise. If one or more of these or other risks or uncertainties materialize, or if NSA’s and Public Storage’s underlying assumptions prove to be incorrect, NSA’s, Public Storage’s and the combined company’s actual results may vary materially from what NSA or Public Storage may have expressed or implied by these forward-looking statements. NSA and Public Storage caution not to place undue reliance on any of NSA’s or Public Storage’s forward-looking statements. Furthermore, new risks and uncertainties arise from time to time, and it is impossible for us to predict those events or how they may affect NSA or Public Storage.

No Offer or Solicitation

This communication is for informational purposes only and is not intended to, and shall not, constitute an offer to sell or the solicitation of an offer to sell or the solicitation of an offer to buy any securities or a solicitation of any vote or approval, nor shall there be any offer, solicitation or sale of securities in any jurisdiction in which such offer, solicitation, or sale would be unlawful prior to registration or qualification under the securities laws of any such jurisdiction. No offer of securities shall be made except by means of a prospectus meeting the requirements of Section 10 of the Securities Act.

Important Additional Information and Where to Find It

(when they become available) and other documents filed with the SEC by NSA and/or Public Storage, which contain important information, through the website maintained by the SEC at www.sec.gov. Investors and security holders will be able to obtain free copies of the documents filed by NSA with the SEC on NSA’s website at https://ir.nsastorage.com/sec-filings/all-sec-filings or by contacting NSA Investor Relations at ghoglund@nsareit.net. Security holders will also be able to obtain free copies of the documents filed by Public Storage with the SEC on Public Storage’s website at https://investors.publicstorage.com/financial-reports/sec-filings or by contacting Public Storage Investor Relations at investorrelations@publicstorage.com.

Participants in the Solicitation

NSA, Public Storage, their respective trustees and certain of their respective executive officers may be deemed to be participants in the solicitation of proxies from NSA’s shareholders in respect of the proposed transaction. Information about the trustees and executive officers of NSA, including a description of their direct or indirect interests, by security holdings or otherwise, is set forth in NSA’s proxy statement for its 2025 Annual Meeting of Shareholders under the headings “Our Board,” “How We Are Paid,” “Compensation Discussion and Analysis,” “Summary Compensation and Other Tables,” “Severance and Change in Control Arrangements,” “Certain Relationships and Related Transactions” and “Shareholder Ownership Information,” which was filed with the SEC on March 28, 2025, and in NSA’s Annual Report on Form 10-K for the fiscal year ended December 31, 2025, which was filed with the SEC on February 26, 2026. To the extent holdings of NSA’s securities by its trustees or executive officers have changed since the amounts set forth in NSA’s definitive proxy statement for its 2025 Annual Meeting of Shareholders, such changes have been or will be reflected on an Initial Statement of Beneficial Ownership of Securities on Form 3, Statement of Changes in Beneficial Ownership on Form 4 or Annual Statement of Changes in Beneficial Ownership on Form 5, in each case filed with the SEC, and available on the SEC’s website at www.sec.gov. Information about the trustees and executive officers of Public Storage, including a description of their direct or indirect interests, by security holdings or otherwise, is set forth in Public Storage’s proxy statement for its 2025 Annual Meeting of Shareholders under the headings “2024 Trustee Compensation,” “Our Named Executive Officers,” “Compensation Discussion and Analysis,” “Executive Compensation Tables,” “Potential Payments Upon Termination or Change in Control,” “Outstanding Equity Awards at 2024 Fiscal Year End,” “Related Person Transactions” and “Share Ownership of Trustees and Management,” which was filed with the SEC on March 28, 2025, in Public Storage’s Annual Report on Form 10-K for the fiscal year ended December 31, 2025, which was filed with the SEC on February 12, 2026, in Public Storage’s Form 8-K filed with the SEC on July 30, 2025, and in Public Storage’s Form 8-K filed with the SEC on February 12, 2026. To the extent holdings of Public Storage’s securities by its trustees or executive officers have changed since the amounts set forth in Public Storage’s definitive proxy statement for its 2025 Annual Meeting of Shareholders, such changes have been or will be reflected on an Initial Statement of Beneficial Ownership of Securities on Form 3, Statement of Changes in Beneficial Ownership on Form 4, or Annual Statement of Changes in Beneficial Ownership on Form 5, in each case filed with the SEC and available on the SEC’s website at www.sec.gov. Other information regarding the participants in the proxy solicitations and a description of their direct and indirect interests, by security holdings or otherwise, will be contained in the Registration Statement, the Proxy Statement/Prospectus and other relevant materials to be filed with the SEC regarding the proposed transaction when such materials become available. Investors and security holders should read the Registration Statement and the Proxy Statement/Prospectus carefully when they become available before making any voting or investment decisions. You may obtain free copies of these documents from NSA or Public Storage using the sources indicated above.

The following email was sent on behalf of H. Thomas Boyle, Public Storage’s current Chief Investment Officer and incoming Chief Executive Officer, to Public Storage’s field employees on March 16, 2026.

To: Field Employees

Subject: PS 4.0 Milestone: Public Storage Announces Acquisition of NSA Storage

LOGO

Sent on behalf of Tom Boyle, Incoming Chief Executive Officer

Dear Public Storage Team,

In February, we shared our PS4.0 vision to secure our future as the leader in self-storage. Today, we are excited to share our first major milestone under PS4.0: Public Storage has reached an agreement to acquire NSA Storage. You can read more details in the press release we issued this morning.

NSA has one of the largest nationwide portfolios of self-storage properties. Together, there is no question that Public Storage will be the biggest owner and operator of self-storage sites in the United States. We look forward to adding NSA’s more than 500,000 customers to our platform where they will greatly benefit from our digital ecosystem and ability to transact 24/7 through the channel of their choice. The combined company will have ~4,600 stores spanning 327 million square feet in 42 states. This is an exciting opportunity to bring the strength, efficiency, and top-quality service of the Public Storage platform to many more people in more markets.

We’re also excited about what this means for our team members. Increased growth means increased opportunities for our people across a larger, diversified store footprint. It is thanks to the hard work of every one of you that we have clearly become the platform the rest of the industry wants to become part of. Our properties are better managed and more desired by customers than any in the self-storage business.

I’m looking forward to sharing more about how we bring to life the benefits from this transaction, as we move towards closing in the second half of 2026. NSA’s leadership and team members have built a strong portfolio, and we look forward to welcoming them to Public Storage.

As we move forward, our focus needs to remain on the exceptional service and quality that you deliver for over two million customers every single day.

Since acquisitions can sometimes bring questions from external parties, if you receive a question from media, please do not comment but rather direct those inquiries to Nathan Vitan at [***]. We’ve also attached a toolkit for your use.

I want to thank the entire team for the tremendous work you do to put Public Storage in a position of strength. As I take on my new role soon, I’m excited to spend even more time at our properties in the coming weeks and months – and to talking with you about cementing our position as the #1 leader in self-storage!

Tom

+++++++

Cautionary Statement Regarding Forward-Looking Statements

transaction costs and/or unknown or inestimable liabilities; (v) potential litigation relating to the proposed transaction that could be instituted against NSA or its trustees, managers or officers, including resulting expense or delay and the effects of any outcomes related thereto; (vi) the risk that disruptions from the proposed transaction, including diverting the attention of NSA and Public Storage management from ongoing business operations, will harm NSA’s and Public Storage’s businesses during the pendency of the proposed transaction or otherwise; (vii) certain restrictions during the pendency of the business combination that may impact NSA’s and Public Storage’s ability to pursue certain business opportunities or strategic transactions; (viii) the possibility that the business combination may be more expensive to complete than anticipated, including as a result of unexpected factors or events; (ix) the occurrence of any event, change or other circumstance that could give rise to the termination of the merger agreement, including in circumstances requiring NSA to pay a termination fee; (x) the effect of the announcement of the proposed transaction on the ability of NSA and Public Storage to operate their respective businesses and retain and hire key personnel, and to maintain favorable business relationships; (xi) risks related to the market value of Public Storage common stock to be issued in the proposed transaction; (xii) other risks related to the completion of the proposed transaction and actions related thereto; (xiii) potential business uncertainty, including changes to existing business relationships, during the pendency of the business combination or otherwise that could affect NSA’s or Public Storage’s financial performance; (xiv) other risks related to the completion of the proposed transaction and actions related thereto; (xv) legislative, regulatory and economic developments; (xvi) unpredictability and severity of local, regional, national and international economic, political and catastrophic climates, conditions and events, including but not limited to acts of terrorism, outbreaks of war or hostilities or pandemics, as well as management’s response to any of the aforementioned factors; (xvii) changes in global financial markets, interest rates and foreign currency exchange rates; (xviii) increased or unanticipated competition affecting NSA’s or Public Storage’s properties; (xix) risks associated with acquisitions, dispositions and development of properties, including increased development costs due to additional regulatory requirements related to climate change; (xx) maintenance of Real Estate Investment Trust status, tax structuring and changes in income tax laws and rates; (xxi) risks related to NSA’s and Public Storage’s investments in ventures, including NSA’s and Public Storage’s respective abilities to establish new ventures; (xxii) environmental uncertainties, including risks of natural disasters; (xxiii) those risks and uncertainties set forth in NSA’s and Public Storage’s Annual Reports on Form 10-K for the year ended December 31, 2025 under the headings “Forward-Looking Statements” and “Cautionary Statement Regarding Forward-Looking Statements,” respectively, and “Risk Factors,” as such risk factors may be amended, supplemented or superseded from time to time by other reports filed by NSA or Public Storage, as the case may be, with the Securities and Exchange Commission (the “SEC”) from time to time, which are available via the SEC’s website at www.sec.gov; and (xxiv) those risks that will be described in the Registration Statement and Proxy Statement/Prospectus that will be filed with the SEC in connection with the proposed transaction and available from the sources indicated below. There can be no assurance that the proposed transaction will be completed, or if it is completed, that it will close within the anticipated time period. These factors should not be construed as exhaustive and should be read in conjunction with the other forward-looking statements. Forward-looking statements relate only to events as of the date on which the statements are made. Neither NSA nor Public Storage undertakes any obligation to publicly update or review any forward-looking statement except as required by law, whether as a result of

new information, future developments or otherwise. If one or more of these or other risks or uncertainties materialize, or if NSA’s and Public Storage’s underlying assumptions prove to be incorrect, NSA’s, Public Storage’s and the combined company’s actual results may vary materially from what NSA or Public Storage may have expressed or implied by these forward-looking statements. NSA and Public Storage caution not to place undue reliance on any of NSA’s or Public Storage’s forward-looking statements. Furthermore, new risks and uncertainties arise from time to time, and it is impossible for us to predict those events or how they may affect NSA or Public Storage.

No Offer or Solicitation

Important Additional Information and Where to Find It

In connection with the proposed transaction between NSA and Public Storage, Public Storage intends to file with the SEC a registration statement on Form S-4 (the “Registration Statement”) that will include a proxy statement of NSA that also constitutes a prospectus of Public Storage (the “Proxy Statement/Prospectus”). A definitive Proxy Statement/Prospectus will be mailed to NSA’s shareholders seeking their approval of the proposed transaction and other related matters. Each of NSA and Public Storage may also file other relevant documents with the SEC regarding the proposed transaction. This communication is not a substitute for the Registration Statement, Proxy Statement/Prospectus or any other document that NSA or Public Storage (as applicable) may file with the SEC in connection with the proposed transaction. BEFORE MAKING ANY VOTING OR INVESTMENT DECISION, INVESTORS AND SECURITY HOLDERS OF NSA AND Public Storage ARE URGED TO READ CAREFULLY AND IN THEIR ENTIRETY THE REGISTRATION STATEMENT, THE PROXY STATEMENT/PROSPECTUS AND ANY OTHER RELEVANT DOCUMENTS THAT ARE FILED OR WILL BE FILED WITH THE SEC, AS WELL AS ANY AMENDMENTS OR SUPPLEMENTS TO THESE DOCUMENTS WHEN THEY BECOME AVAILABLE WITH THE SEC BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION ABOUT THE PROPOSED TRANSACTION AND RELATED MATTERS. Investors and security holders will be able to obtain free copies of the Registration Statement and the Proxy Statement/Prospectus (when they become available) and other documents filed with the SEC by NSA and/or Public Storage, which contain important information, through the website maintained by the SEC at www.sec.gov. Investors and security holders will be able to obtain free copies of the documents filed by NSA with the SEC on NSA’s website at https://ir.nsastorage.com/sec-filings/all-sec-filings or by contacting NSA Investor Relations at ghoglund@nsareit.net. Security holders will also be able to obtain free copies of the documents filed by Public Storage with the SEC on Public Storage’s website at https://investors.publicstorage.com/financial-reports/sec-filings or by contacting Public Storage Investor Relations at investorrelations@publicstorage.com.

Participants in the Solicitation

SEC Form 425 filed by National Storage Affiliates Trust