Silver extended its summer rally on Friday, with spot prices jumping almost 3% to roughly $38.38 an ounce, the highest level since September 2011. Futures on the metal briefly touched $38.50 an ounce, reinforcing chart-watchers’ view that bullion is breaking out of a multi-year range. The advance widened silver’s year-to-date outperformance versus gold and revived speculation that the metal could challenge its 2011 peak near $48 an ounce later this year. Gold also firmed, rising about $30 on the day, yet shares of major silver and gold miners and related exchange-traded funds such as SLV and PSLV were little changed, suggesting investor caution toward equities despite the price surge.