On Friday, U.S. solar energy stocks gained strength. At the time of writing, Sunrun (RUN.US), Daqo New Energy (DQ.US), and Canadian Solar (CSIQ.US) were up more than 7%, while JinkoSolar (JKS.US) and Array Technologies (ARRY.US) rose over 6%, and Enphase Energy (ENPH.US) climbed more than 4%. The rally comes as the U.S. Treasury Department is set to release tax guidance next week that could threaten the financial viability of hundreds of clean energy projects across the country. This decision may overturn existing rules and intensify the Trump administration's policy tightening on the wind and solar industries.

The core controversy stems from adjustments to the eligibility criteria for clean energy tax credits. For years, developers could qualify for tax subsidies by meeting the "commence construction" requirement if they incurred at least 5% of a project's planned costs before a specific deadline. However, last month, Trump signed an executive order directing the Treasury to significantly raise this threshold or require developers to provide more proof of construction progress. Analysts note that if the new rules take effect, many projects relying on tax credits for profitability could lose eligibility and may even be forced to cancel.