Wall Street's main indexes opened flat to slightly higher in Tuesday's shortened trading session, with U.S. stocks entering a historically strong period before rounding off their second consecutive year of gains.

Stocks are broadly higher in trading on Wall Street, led by gains in Big Tech stocks. The S&P 500 was up 0.7% Tuesday.

Stocks shook off a choppy start to finish higher Monday, as Wall Street kicked off a holiday-shortened week. The S&P 500 ended 0.7% higher after having been down 0.5% in the early going. The Dow Jones Industrial Average also recovered from an early slide to eke out a 0.2% gain. The tech-heavy Nasdaq composite rose 1%.