The Nasdaq led gains among Wall Street indexes on Wednesday after a robust forecast from Microsoft supported optimism about the third-quarter earnings season, while a decline in oil prices hurt shares of energy companies. The S&P 500 index and the Dow Jones Industrial Average struggled for direction in the first hour of trading, with seven of the 11 major S&P 500 sectoral indexes falling. Microsoft Corp. jumped 3.6 percent after it forecast a strong end to the calendar year, helped by its booming cloud business. Google-owner Alphabet Inc. gained 3.3 percent after reporting a record quarterly profit on a surge in ad sales. Their shares, coupled with other mega-cap growth names Amazon.com, and Tesla Inc., provided the biggest boost to the Nasdaq index. “Today feels exactly like the calm before the storm ahead of a pile of earnings that is due tomorrow and everyone wants to know how the supply-chain …