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First Solar drops ITC patent case, shifts focus to lawsuits against rivals

By Thomson Reuters Sep 16, 2026 | 1:55 PM

(Fixes spelling of Jinko Solar)

Sept 16 (Reuters) – U.S. solar panel maker First Solar Inc said on Wednesday it would withdraw a patent infringement complaint before the U.S. International Trade ​Commission and instead focus on pursuing lawsuits in federal ‌court against rivals over a leading solar technology.

• The Phoenix-based company said it plans to withdraw its Section 337 complaint and seek termination of the ITC investigation without prejudice, leaving open the possibility of refiling later.

• First Solar ‌said ​it will continue pursuing patent lawsuits in ⁠federal court against affiliates ⁠of Canadian Solar, Jinko Solar, T1 Energy and Trina Solar, cases that had been paused pending the ITC proceeding.

• TOPCon, short for tunnel oxide passivated contact, is a high-efficiency crystalline silicon ​solar cell technology that has become one of the dominant solar technologies. First Solar does not manufacture silicon-based products, which include ⁠TOPCon, and instead makes cadmium telluride ⁠panels.

• First Solar acquired the TOPCon patents through its ​2013 purchase of TetraSun and began investigating potential infringement by major ​solar manufacturers in 2024.

• T1 Energy said it would defend ‌itself against any remaining claims: “T1 Energy is the only American company that both owns patents to high efficiency TOPCon solar and currently manufactures TOPCon solar modules,” spokesperson Russell Gold said. “We are pleased ⁠that First Solar voluntarily withdrew what we believe was a flawed Sec. 337 complaint that would have slowed needed energy production at a time ⁠when the United ‌States needs all the affordable electricity we can ⁠produce.”

• Canadian Solar, Jinko Solar and Trina Solar ​did not ‌immediately respond to requests for comment.

• First Solar ​said the ⁠decision to withdraw the complaint followed the Trump administration’s recent proclamation imposing trade measures on imports of polysilicon and related solar products.

• Shares of First Solar were down about 5% on Wednesday and touched their lowest level in roughly five months.

(Reporting by Nichola Groom, Editing ​by Nick Zieminski)