S&P 500 top movers: Major tech stocks post strong gains, energy stocks lag

• S&P 500 Index struggles to build on Monday's gains.
• Tech stocks are among top gainers on Tuesday.
• Falling crude oil prices weigh on energy stocks. 

The S&P 500 Index (SPX) opened little changed on Tuesday and continues to trade in a choppy way as investors stay on the sidelines ahead of the first US presidential debate. As of writing, the SPX was down 0.13% on the day at 3,346.

S&P 500 top movers

Technology stocks are among the best performers of the day. As of writing, Paycom Software Inc (PAYC: NYSE) shares were up 4.02% at $302.48. Furthermore, DXC Technology Co (DXC: NYSE), Advanced Micro Devices Inc (AMD: NASDAQ), Arista Networks Inc (ANET: NYSE) and NVIDIA Corp (NVDA: NASDAQ) shares are up between 3.7% and 3%.

On the other hand, the sharp decline witnessed in crude oil prices is weighing on energy shares. At the moment, the barrel of West Texas Intermediate is losing 3.6% on the day at $39.10. Apache Corp (APA: NASDAQ), National Oilwell Varco Inc (NOV: NYSE) and Halliburton Co (HAL: NYSE) shares are down 6.7%, 5.9% and 5%, respectively.