Silver Plummets 27% in Week, Most Since 1975; Gold Futures Gain

May 06, 2011, 3:20 PM EDT

May 6 (Bloomberg) -- Silver futures fell, capping the biggest weekly plunge since at least 1975, on mounting sales by investors following increases in Comex margin requirements. Gold rebounded, halting a three-day slide.

Silver tumbled 27 percent this week after CME Group Ltd., the Comex owner, boosted the cash amount needed for a speculative position by 84 percent in two weeks. Yesterday, holdings of the metal in exchange-traded products dropped the most in three years. Gold had the largest weekly drop in a year.

“At the close of business on Monday, silver’s got another bump in margins,â€