US solar stocks rise after Treasury eases subsidy rules

Shares of US solar companies gained after the Treasury Department issued guidance on clean energy subsidies that proved less restrictive than expected.

The new rules, announced on 15 August, clarify what qualifies as a solar or wind project under construction, a requirement for accessing federal tax credits covering 30% of project costs. Developers must now show physical work on-site, not just financial commitments. The Treasury also retained the four-year window for completing projects once construction begins.

Industry groups had feared tighter timelines and higher upfront cost thresholds. While some developers criticised the revisions, analysts said the guidance was more favourable than anticipated.

The MAC Global Solar Energy Index rose 4% following the announcement. Sunrun’s shares jumped 9% and First Solar gained 8.6%.

The subsidies are part of the One Big Beautiful Bill Act, signed on 4 July 2025. To qualify, projects must start construction by July 2026 or begin operations by end-2027. The scheme replaces earlier legislation that had extended access to credits until 2032.