Powell's testimony boosts Wall Street to close higher.

The S&P 500 and Nasdaq closed higher as Federal Reserve Chairman Jerome Powell suggested the central bank has not reached the end of its tightening cycle, but provided reassurance that the Fed would proceed with caution. The tech-heavy Nasdaq's robust gain got a boost from momentum stocks led by Amazon.com, Apple Inc, and Microsoft Corp, while the S&P 500's advance was more modest. Investors were taken by surprise when the Bank of England implemented a larger-than-expected 50 basis point rate hike to tackle Britain's stubborn inflation, further evidence that hot price growth remains a global economic headwind.