The Los Angeles Business Journal’s index of the largest local public companies closed down for the week ended May 21 amid overall stock market volatility and disappointing financial reports from local companies.

The weighted LABJ index closed down 2.8 percent to 117.72, with decliners outpacing gainers 154 to 26.

The biggest decliner was American Apparel Inc., which plunged 47 percent, after the Los Angeles manufacturer and retailer reported a large first quarter operating loss in its first quarter and warned it may default on some debt.

Songzai International Holding Group Inc. ended the week down 34 percent to $4.70 after the City of Industry company, which is developing coal resources in China, announced lower first quarter profit and revenue.

Broadway Financial Corp. dropped 24 percent to $3.39 after the Los Angeles thrift disclosed that the federal Office of Thrift Supervision is likely to require it to increase its allowance for loan losses as of the end of 2009 by a substantial amount.

Hot Topic Inc. fell 15 percent after the Vernon teen retailer posted a first quarter net loss due to declining revenue at its flagship stores and an online unit.

Among the few significant gainers was Westlake Village athletic footwear maker K-Swiss Inc., which jumped 18 percent to $12.56 on an analyst’s upgrade. The company’s stock took a hit earlier in the month on news of an overseas plant closure.