After a tumultuous week on Wall Street during which the Dow Jones industrial average lost as much as 450 points only to gain virtually all of it back, the Los Angeles Business Journal’s index of the 200 largest public companies rallied to gain 5 percent.

Leading the way was Los Angeles-based online music retailer Napster Inc., which added 94 percent to $2.58 after retail giant Best Buy Inc. bought the struggling company with plans to expand its offerings.

Local banks surprisingly benefited from the market turmoil, mainly from short sellers covering their positions as the Securities and Exchange Commission temporarily banned short sales. FirstFed Financial Corp. of Los Angeles soared 64 percent to $19.75 while Pasadena’s East West Bancorp jumped $32 percent to $17.65.

However, two local real estate companies saw shares fall sharply as investors fled companies with large pools of debt. Los Angeles-based InterGroup Corp. was down 23 percent to $13.02, and downtown’s largest landlord, Maguire Property Group Inc., shed 21 percent to $8.14.

Also getting hit was Chatsworth microturbine manufacturer Capstone Turbine Corp., which lost as much as 36 percent during the week after announcing plans to issue 21.5 million shares to raise money for product development and corporate growth. It later rebounded to close at $1.52, down 14 percent.