AMERICAN SUPERCONDUCTOR CORP /DE/ (AMSC): M&A transaction — AMSC buys Comtrafo for BRL 300M cash, 2.4M shares, plus earnout up to BRL 382.5M

Stock Exchange Agreement, AMSC Brazil, directly or indirectly, purchased all of the issued and outstanding shares of Comtrafo (collectively, the “ Target Interests ”) for (a) (i) 300,000,000 Brazilian Real in cash; and (b) 2,417,142 restricted shares of the Company’s common stock, $0.01 par value per share (the “ AMSC Shares ”) that were paid and issued, respectively,

On December 5, 2025 (the “ Closing Date ”), Mardin Participações Ltda., an entity incorporated in Brazil (“ AMSC Brazil ”) and a wholly-owned subsidiary of American Superconductor Corporation, a Delaware corporation (the “ Company ”), entered into a Stock Exchange Agreement (the “ Stock Exchange Agreement ”) with each of the sellers listed on the signature pages thereto (each, a “ Stockholder ” and collectively, the “ Stockholders ”), Comtrafo Indústria de Transformadores Elétricos S.A., an entity incorporated in Brazil (“ Comtrafo ”), Irineu Minato, an individual, solely in his capacity as the stockholder representative thereunder (the “ Stockholder Representative ”), the stockholder group members listed on Schedule I thereto (each, a “ Stockholder Group Member ” and collectively, the “ Stockholder Group Members ”), and the Company solely for purposes of Section 1.1(a), Article IV, Section 5.5 and Section 5.7 of the Stock Exchange Agreement. Additionally on the Closing Date, pursuant

In addition, pursuant to the Real Property Agreements, AMSC Brazil through Comtrafo purchased certain real estate assets and transportation assets of Comtrafo for 155,564,538 Brazilian Real and 13,376,676 Brazilian Real, respectively, in cash.