US stock indexes closed slightly lower on Friday, with the S&P 500, Dow Jones, and Nasdaq all falling less than 0.1%. But the real surprise came from silver prices, soaring nearly 8% due to supply constraints. With only three trading days left, the S&P 500 has climbed nearly 18% this year. Find out why Target's shares surged and how U.S. crude oil took a 2.8% hit. What's next for the markets as the year comes to a close?