S&P 500, Nasdaq close at record highs as bipartisan infrastructure deal spurs economic optimism

Xinhua/Wang Ying/ Getty ImagesUS stocks closed at record highs on Thursday as a bipartisan deal for an infrastructure bill helped boost economic optimism.The S&P 500 and Nasdaq 100 closed at record highs, while the Dow Jones surged more than 300 points.Weekly jobless claims resumed their downward trend on Thursday, falling to 411,000.Sign up here for our daily newsletter, 10 Things Before the Opening Bell.US stocks hit all-time highs on Thursday, with the S&P 500 and Nasdaq 100 closing a