The right time for investors to make a move may be sooner than they think. - MarketWatch/iStockphoto The investments that have made the biggest gains this year are ending on a high note. Silver SI00, gold GC00, shares of Nvidia NVDA, and stock-market indexes like the Dow Jones Industrial Average DJIA, the S&P 500 SPX and the Nasdaq composite COMP have all surged in December, capping in some cases a remarkable run. Silver, up over 150% this year, rose more than 4% on the day after Christmas. Most Read f ...