Alto Neuroscience Announces Closing of Upsized Initial Public Offering and Full Exercise of the Underwriters' Option to Purchase Additional Shares

Alto Neuroscience, Inc. ("Alto") (NYSE: ANRO) today announced the closing of its previously announced upsized initial public offering of 9,246,000 shares of common stock, which includes the exercise in full by the underwriters of their option to purchase 1,206,000 additional shares, at a public offering price of $16.00 per share. The aggregate gross proceeds to Alto from the offering were approximately $147.9 million before deducting underwriting discounts and commissions and other offering expenses payable by Alto. All of the shares of common stock were offered by Alto. Alto's common stock is listed on the New York Stock Exchange under the ticker symbol "ANRO."

Jefferies, TD Cowen, Stifel and William Blair acted as joint book-running managers for the offering. Baird acted as lead manager for the offering.

Registration statements relating to these securities have been filed with the Securities and Exchange Commission (the "SEC") and became effective on February 1, 2024. A prospectus relating to and describing the terms of the offering has been filed with the SEC and is available on the SEC's website at www.sec.gov. The offering was made only by means of a written prospectus. A copy of the final prospectus relating to the offering may be obtained from: Jefferies LLC, Attention: Equity Syndicate Prospectus Department, 520 Madison Avenue, New York, NY 10022, by telephone at (877) 821-7388, or by email at [email protected]; Cowen and Company, LLC, 599 Lexington Avenue, New York, NY 10022, by telephone at (833) 297-2926, or by e-mail at [email protected]; Stifel, Nicolaus & Company, Incorporated, Attention: Syndicate, One Montgomery Street, Suite 3700, San Francisco, CA 94104, by telephone at (415) 364-2720, or by e-mail at [email protected]; or William Blair & Company, L.L.C., Attention: Prospectus Department, 150 North Riverside Plaza, Chicago, IL 60606, by telephone at (800) 621-0687, or by email at [email protected].

This press release shall not constitute an offer to sell, or the solicitation of an offer to buy these securities, nor shall there be any sale of these securities in any state or jurisdiction in which such offer, solicitation, or sale would be unlawful prior to registration or qualification under the securities laws of any such state or jurisdiction.

About Alto Neuroscience

Alto Neuroscience is a clinical-stage biopharmaceutical company with a mission to redefine psychiatry by leveraging neurobiology to develop personalized and highly effective treatment options. Alto's Precision Psychiatry Platformtm measures brain biomarkers by analyzing EEG activity, neurocognitive assessments, wearable data, and other factors to better identify which patients are more likely to respond to Alto product candidates. Alto's clinical-stage pipeline includes novel drug candidates in depression, PTSD, schizophrenia, and other mental health conditions.