Filed pursuant to Rule 424(b)(5)
Registration No. 333-283905
AMENDMENT NO. 1 dated March 12, 2026
TO PROSPECTUS SUPPLEMENT dated February 26, 2026
(To Prospectus dated December 18, 2024)
$500,000,000
Applied Optoelectronics, Inc.
Common Stock
This Amendment No. 1 to prospectus supplement, or this amendment, amends our prospectus supplement dated February 26, 2026 (the “prospectus supplement”). This amendment should be read in conjunction with the prospectus supplement and the prospectus dated December 18, 2024, both of which are to be delivered with this amendment. This amendment only amends those sections of the prospectus supplement listed in this amendment; all other sections of the prospectus supplement remain as is.
On February 26, 2026, we have entered into an Equity Distribution Agreement with Raymond James & Associates, Inc. (“Raymond James”) and Needham & Company, LLC (“Needham”), or the sales agreement, relating to shares of our common stock offered by the prospectus supplement. On March 12, 2026, we amended the sales agreement to increase the total amount of common stock that we may offer and sell under the sales agreement from $250,000,000 to $500,000,000 (which amount includes what we have already sold pursuant to the sales agreement prior to the date of this amendment) from time to time through Raymond James and Needham, acting as agents (each, an “Agent” and collectively, the “Agents”). As of March 12, 2026, we have sold an aggregate of 2,476,307 shares of our common stock pursuant to the sales agreement for gross proceeds of approximately $249,999,983, and we may offer and sell an additional aggregate offering price of approximately $250,000,017 following this amendment.
Our common stock is listed on The Nasdaq Global Market under the symbol “AAOI.” On March 11, 2026, the last reported sale price of our common stock on The Nasdaq Global Market was $127.01 per share.
Sales of our common stock, if any, under this prospectus supplement, as amended by this amendment, may be made in sales deemed to be “at-the-market” equity offerings as defined in Rule 415 promulgated under the Securities Act of 1933, as amended, or the Securities Act, including sales made directly on or through The Nasdaq Global Market, the existing trading market for our common stock, sales made to or through a market maker other than on an exchange or otherwise, in negotiated transactions at market prices prevailing at the time of sale or at prices related to such prevailing market prices, and any other method permitted by law, including in privately negotiated transactions. The Agents are not required to sell any specific number or dollar amount of securities, but will act as sales agents and use commercially reasonable efforts to sell on our behalf all of the shares of common stock requested to be sold by us, consistent with their normal trading and sales practices, on mutually agreed terms between the Agents and us. There is no arrangement for funds to be received in any escrow, trust or similar arrangement.
Except as otherwise described in the sales agreement, the Agents will be entitled to compensation at a commission rate of up to 2.0% of the gross sales price per share sold. In connection with the sale of our common stock on our behalf, the Agents may be deemed to be “underwriters” within the meaning of the Securities Act and the compensation of the Agents may be deemed to be underwriting commissions or discounts. We have also agreed to provide indemnification and contribution to the Agents with respect to certain liabilities, including liabilities under the Securities Act and the Securities Exchange Act of 1934, as amended, or Exchange Act.
INVESTING IN OUR SECURITIES INVOLVES SIGNIFICANT RISKS. YOU SHOULD REVIEW CAREFULLY THE “RISK FACTORS” BEGINNING ON PAGE
S-3 OF THIS AMENDMENT AND UNDER SIMILAR HEADINGS IN THE OTHER DOCUMENTS THAT ARE INCORPORATED BY REFERENCE INTO THIS PROSPECTUS SUPPLEMENT BEFORE INVESTING IN OUR SECURITIES.
Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or passed upon the adequacy or accuracy of this prospectus. Any representation to the contrary is a criminal offense.
RAYMOND JAMESNEEDHAM & COMPANY
The date of this amendment to prospectus supplement is March 12, 2026.