Dow, S&P 500 edge to records after US-China trade deal signed

The Dow and S&P 500 edged to records Wednesday following a volatile session after the US and China signed a long-awaited trade agreement. The Dow Jones Industrial Average gained 0.3 percent to finish at 29,030.22, and the broad-based S&P 500 added 0.2 percent to 3,289.30.

The tech-rich Nasdaq Composite Index climbed 0.1 percent to end at 9.258.70. Analysts said the choppy trading session reflects worries about lofty US stock valuations following the market's surge since October.