The U.S. International Trade Commission (ITC) has officially initiated a Section 337 investigation into tunneling oxide layer passivation contacts for solar cells, modules, and panels, with several Chinese companies listed as respondents.

According to the China Trade Remedy Information Network, on March 26, the U.S. International Trade Commission (ITC) voted to initiate a Section 337 investigation (Investigation No. 337-TA-1494) against certain tunneling oxide passivated contact (TOPCon) solar cells, modules, panels, components thereof, and downstream products (Certain TOPCon Solar Cells, Modules, Panels, Components Thereof, and Products Containing Same).

On February 24, 2026, First Solar, Inc. of Phoenix, Arizona, filed an application with the U.S. ITC to institute a Section 337 complaint investigation, alleging that the product exported to the United States, imported into the United States, and sold in the United States violates Section 337 of the U.S., requesting that the U.S. ITC issue a general exclusion order or a limited exclusion order and a cease-and-desist order, based on infringement of U.S. registered patent No. 9130074.

The following entities are named as respondents: AXITEC, LLC of Radnor, PA; AXITEC Energy GmbH & Co. KG of Germany; AXITEC SOLAR, LLC of Newark, Delaware; Canadian Solar Inc. of Canada; JinkoSolar Co., Ltd. of China; Canadian Solar (USA) Inc. of Walnut Creek, CA; Canadian Solar Manufacturing (Thailand) Co., Ltd. of Thailand; Canadian Solar US Module Manufacturing Corporation of Mesquite, TX; Canadian Solar International Ltd. of Hong Kong Special Administrative Region; JA Solar Technology Co., Ltd., Beijing, China, Beijing Jingao Energy Technology Co., Ltd.; JA Solar USA, Inc. of San Jose, CA; JA Solar AZ, LLC of Phoenix, AZ; JA Solar International, Ltd. of Hong Kong Special Administrative Region; JA Solar Vietnam Co., Ltd. of Vietnam; JinkoSolar Holding Co., Ltd., Jiangxi Province, China, JinkoSolar Energy Holding Company Limited; Jinko Solar Co., Ltd., Jiangxi Province, China, JinkoSolar Co., Ltd.; Jinko Solar (Vietnam) Industries Co. Ltd. of Vietnam; Jinko Solar Technology Sdn. Bhd. of Malaysia; Zhejiang Jinko Solar Co., Ltd., Zhejiang Province, China; Zhejiang Jinko Solar Energy Co., Ltd.; JinkoSolar (U.S.) Inc. of Campbell, CA; JinkoSolar (U.S.) Manufacturing Inc. of Dover, DE; JinkoSolar (U.S.) Industries Inc. of Jacksonville, FL; Mundra Solar PV Limited of India; Mundra Solar Energy Ltd. of India; Adani Green Energy Ltd. of India; Philadelphia Solar LLC of Jordan; Philadelphia Solar USA Inc. of San Mateo, CA; Hanwha Q CELLS USA Inc. of Dalton, GA; Hanwha Q CELLS America Inc. of Irvine, CA; Hanwha Q CELLS USA Corp. of Irvine, CA; Hanwha Solutions Corporation of Korea; Jiangsu Runergy New Energy Technology Co., Ltd., Yancheng City, Jiangsu Province, China; Runergy USA Inc. of Pleasanton, CA; Runergy Alabama Inc. of Huntsville, AL; Runergy USA Trading LLC of Dover, DE; Runergy PV Technology (Thailand) Co., Ltd. of Thailand; Trina Solar Co., Ltd., Xinbei District, Jiangsu Province, China; Trina Solar (U.S.), Inc. of Fremont, CA; Trina Solar Energy Development Co., Ltd. of Vietnam; Changzhou Trina Solar Energy Co., Ltd. of China; Trina Solar Yiwu Technology Co., Ltd. of China; T1 Energy, Inc. of Austin, TX; T1 G1 Dallas Solar Module LLC of Wilmer, TX; Vietnam Sunergy Joint Stock Company of Vietnam; VSUN Solar USA Inc. of Fremont, CA; Toyo Co., Ltd. of Japan; and Toyo Solar Texas, LLC of Humble, TX.

Within 45 days after the institution of the case, the U.S. International Trade Commission will determine the investigation’s end date. Except for situations in which the Office of the U.S. Trade Representative disapproves the matter for policy reasons, the remedial orders issued by the U.S. International Trade Commission in Section 337 cases will take effect on the date of issuance and will have final effect starting from the 60th day after the date of issuance.

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