(Bloomberg) -- Clean-tech stocks rose to some of their highest levels in months after Democrats won the backing of Arizona Senator Kyrsten Sinema for their bill to spend $370 billion on climate change measures. 

Solar company Sunrun Inc. climbed as much as 11% to the highest since January before giving back some of those gains. Energy storage and software provider Stem Inc. jumped 15% to a six-month high before easing. Hydrogen and fuel cell company Plug Power Inc. rose as much as 6.7% to the highest since April. 

Read: The US Climate Bill Could Make Now the Best Time to Go Solar

While the bill no longer carries many of the tax changes and social spending once proposed, it is considered a major boost to the transition away from fossil fuels. It contains a series of long-term tax incentives for solar, wind and hydrogen projects, particularly using technology made in the US. Its passage will require the votes of all Senate Democrats, and Sinema made her support contingent on dropping a proposed levy on wealthy hedge fund managers. 

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