US stocks had ended a volatile session barely lower on Tuesday as a late-day rally led by materials and healthcare shares offset another big drop in oil prices.
Energy was the day's weakest sector, with the index falling 2.5 per cent as US crude settled 5.9 per cent lower.
Shares of Anadarko Petroleum dropped 7 per cent to $37.24. The company announced late in the session that it was cutting its dividend, preserving cash at a time when sliding oil prices have fuelled losses.
Pfizer, up 1.9 per cent, and Gilead, up 2.3 per cent, gave the biggest boosts to the S&P 500, while the S&P healthcare index rose 0.7 per cent, the second-best performing sector of the day after materials, up 1.2 per cent.
But the late-day rally was fairly broad-based, suggesting a possible reversal in sentiment.
"Perhaps there's some optimism surrounding Fed chair (Federal Reserve Chair Janet) Yellen's talk tomorrow in front of the House banking committee. There may be some hope there that she's going to say something to buoy the markets," said Peter Jankovskis, co-chief investment officer at OakBrook Investments LLC in Lisle, Illinois.
Yellen is expected to defend the US central bank's first rate hike in a decade and likely insist that further rises this year remain on track, albeit at a slower pace, when she addresses Congress on Wednesday.
The Dow Jones industrial average closed down 12.67 points or 0.08 per cent to 16,014.38, the S&P 500 lost 1.23 points or 0.07 per cent to 1,852.21 and the Nasdaq Composite dropped 14.99 points or 0.35 per cent to 4,268.76.
The S&P 500 bounced 33 points from its session low to its high.
US stock indexes have struggled for most of 2016, falling sharply on increasing worries of a global economic slowdown.
Stephen Massocca, chief investment officer at Wedbush Equity Management LLC in San Francisco, said "pockets of weakness in defensive names" such as real estate investment trusts suggest there is still a lot of nervousness.
The First Trust S&P REIT index fund was down 1.9 per cent.
About 10.0 billion shares changed hands on US exchanges, above the 9.5 billion daily average for the past 20 trading days, according to Thomson Reuters data.
Declining issues outnumbered advancing ones on the NYSE by 2,161 to 935, for a 2.31-to-1 ratio on the downside; on the Nasdaq, 1,824 issues fell and 971 advanced for a 1.88-to-1 ratio favouring decliners.
The S&P 500 posted 9 new 52-week highs and 79 new lows; the Nasdaq recorded 3 new highs and 407 new lows.