U.S. stocks declined to begin their final trading days of 2015, with the Standard & Poor’s 500 Index struggling to advance for the year, as commodity shares tracked a retreat in oil following crude’s strongest weekly gain in four months.

Energy companies resumed their role as the market’s worst performers after a one-week reprieve, with Chevron Corp. and Marathon Oil Corp. dropping at least 1.8 percent. Copper producer Freeport-McMoRan Inc. sank 7.4 percent after climbing 24 percent in the prior five sessions. Walt Disney Co. rose as “Star Wars: The Force Awakens” surged past $1 billion in worldwide sales.

The S&P 500 slipped 0.6 percent to 2,049.06 at 12:46 p.m. in New York, giving up its gain for the year after its best week since Nov. 20. The Dow Jones Industrial Average lost 86.77 points, or 0.5 percent, to 17,465.40. The Nasdaq Composite Index fell 0.7 percent. Trading in S&P 500 shares was 44 percent below the 30-day average for this time of day. This week is shortened, with markets closed for the New Year’s Day holiday on Friday.

Source: Bloomberg