Wall Street dropped on Wednesday as Brent crude slid towards 11-year lows and Apple weighed on the S&P 500 index, which clung to a meager gain for 2015.
The S&P energy sector was the poorest performer among the 10 major sectors, down 1.47 percent after forecasts of a short winter in North America and Europe piled pressure on the oversupplied commodity.
Shares of Exxon lost 1.33 percent while Chevron dipped 1.27 percent.
Apple was the heaviest drag on the S&P 500 and Nasdaq Composite, falling 1.31 percent. Fears of potentially soft iPhone sales have helped push that stock down 9 percent in the past month.
Wednesday's losses undid much a broad rally in the previous session that was similarly influenced by tech and energy stocks.
Netflix and Amazon.com, the S&P 500's top two performers in 2015, dipped 2.02 percent and 0.70 percent respectively.
Nike, this year's best-performing Dow component, fell 1.57 percent.
"There is no consistency and no upside follow-through, which is disturbing, but that's been the pattern all year," said Donald Selkin, chief market strategist at National Securities in New York.
The major indexes deepened their declines in the last few minutes of trade. The Dow Jones industrial average finished 0.66 percent weaker at 17,603.87 points and the S&P 500 lost 0.72 percent to 2,063.36.
The Nasdaq Composite dropped 0.82 percent to 5,065.85.
For the year, the S&P 500 held onto modest 0.2 percent gain, while Nasdaq was up about 7 percent. The Dow, however, was down about 1.2 percent in 2015.
Hobbled by growing global supply and lower demand in Asia, the energy sector has fallen about 24 percent this year, easily the S&P's worst performer. Hurt by a rout in commodities, the materials index has fallen 10 percent in 2015.
Trading volumes were low and were expected to remain thin on Thursday, the last trading day of the year.
Volume on U.S. exchanges was 4.6 billion shares, compared to a 7.4 billion average over the last 20 trading days, according to Thomson Reuters data.
Billionaire investor Carl Icahn's Icahn Enterprises LP agreed to buy Pep Boys-Manny Moe & Jack for about $1 billion, hours after Bridgestone Corp. quit the race for the U.S. auto parts retailer. Pep Boys fell 2.90 percent and Icahn Enterprises dipped 0.97 percent.
Fairchild Semiconductor rose 3.7 percent after it received a revised offer from the Party G Group, with new terms on termination fees if the takeover fails to secure regulatory approvals.
Weight Watchers soared 19 percent, extending gains for the third day after the company launched an advertising campaign last week featuring Oprah Winfrey.
Declining issues outnumbered advancing ones on the NYSE by 2,183 to 898. On the Nasdaq, 2,010 issues fell and 826 rose.
The S&P 500 index showed 15 new 52-week highs and no new lows, while the Nasdaq recorded 54 new highs and 58 new lows.
(Additional reporting by Abhiram Nandakumar in Bengaluru; Editing by Nick Zieminski)