As the Federal Reserve kicks off a long-awaited rate cutting cycle, some investors are wary that richly valued U.S. stocks may have already priced in the benefits of easier monetary policy, making it harder for markets to rise much further.

Indexes rallied Thursday, with tech stocks leading the Nasdaq to rise 2.5% as investors continued to digest Wednesday's jumbo rate cut from the Fed.

U.S. stocks rose after the Federal Reserve lowered its benchmark interest rates by 50 basis points to a range of 4.75% to 5%. That was the first rate cut in over four years that marked the beginning of a monetary-easing cycle in the world's largest economy.