Among other stocks making big moves:
— Best Buy sank 15 percent, losing $2.20 to $11.91. The struggling electronics retailer and one of its founders, Richard Schulze, agreed to give Schulze more time to assemble a bid for the company. That erased most of the gains made Thursday when Best Buy's stock jumped 16 percent following a report that said Schulze would make a bid by the end of the week.
— Silver Bay Realty Trust rose 14 cents to $18.64 in its first day of trading. Silver Bay raised $245.1 million in its initial public offering on Thursday at an IPO price of $18.50. It plans on using the money to buy thousands of single-family homes and rent them out, as the U.S. housing market slowly heals.