Wall Street's main indexes rose on Wednesday as Federal Reserve Chairman Jerome Powell said the domestic economy was in good shape and the central bank saw a "sustained expansion" ahead.

This helped ease nerves on Wall Street, which opened lower after President Donald Trump on Tuesday offered no new details on trade negotiations with China.

The benchmark S&P 500 and Nasdaq had hit new record levels in the run up to Trump's speech, but ended the session off their highs following his address.