Silver

By Claudia Assis
SAN FRANCISCO (MarketWatch) -- Silver futures tanked more than 7% Wednesday after tighter margin requirements sparked a selloff. Gold and other metals also declined as the dollar was stronger. Silver for December delivery retreated $2.04 to $26.87 an ounce on the Comex division of the New York Mercantile Exchange. Late Tuesday, the CME Group increased margin requirements for silver in an apparent effort to curb the metal's volatility. Gold for December delivery settled $10.80 lower at $1,399.30 an ounce, snapping a four-day record-breaking run.