By Echo Wang and Devik Jain (Reuters) – U.S. stocks ended sharply higher on Wednesday after the Federal Reserve delivered a widely expected interest-rate hike, and the S&P 500 recorded its biggest one-day percentage gain in nearly a year. Stocks initially see-sawed after the announcement, then the indexes strengthened. The S&P 500’s advance of almost 3% was the strongest since May 18, 2020. The Federal Reserve on Wednesday raised its benchmark overnight interest rate by half a percentage point and said it would begin shrinking the central bank’s $9 trillion asset portfolio next month in an eff…