Alto Neuroscience, Inc.

In addition to the risks described in our Annual Report, you should carefully consider the other information set forth in this Quarterly Report and the information in our other filings with the SEC, as they could materially affect our business, financial condition or future results of operations. There have been no material changes to the risk factors previously disclosed in “Item 1A. Risk Factors” in our Annual Report other than as set forth below.

We are currently subject to and may be subject to additional future securities class action litigation.

Securities class action litigation has often been instituted against companies following periods of volatility in the market price of a company’s securities. For example, on July 21, 2025, a purported stockholder of the Company filed a putative class action lawsuit against us, certain executive officers, and certain current and former directors in the United States District Court for the Northern District of California alleging violations of the Securities Act and Exchange Act related to our IPO and subsequent public disclosures. In addition, a consolidated stockholder derivative action was filed on behalf of the Company against certain executive officers and certain current and former directors for breach of fiduciary duty, unjust enrichment, abuse of control, gross mismanagement, waste of corporate assets, and violations of the federal securities laws, which claims arise out of the same factual allegations as the putative class action described above. See “Part II, Item 1. Legal Proceedings” in this Quarterly Report for additional information regarding this matter. It is possible that additional lawsuits will be filed, or allegations received from stockholders, with respect to these same or other matters and also naming us and/or our officers and directors as defendants. This litigation could result in substantial costs and a diversion of management’s attention and resources, which would harm our business, results of operations, or financial condition.