The CBOE volatility index, a measure for investors' anxiety, slipped to 20.57 after spiking to a more than two-month high earlier this week.
At 9:51 a.m. ET, the Dow Jones Industrial Average was up 261.03 points, or 0.77%, at 34,282.48, the S&P 500 was up 37.47 points, or 0.91%, at 4,149.97. The Nasdaq Composite was up 127.14 points, or 0.97%, at 13,252.13.
Mega-cap growth stocks, which have been beaten down this week on concerns over their lofty valuations, led gains in early trading with Apple Inc, Amazon.com Inc and Microsoft Corp gaining about 1% each and Tesla Inc adding 2%.