The Los Angeles Business Journal’s index of largest local public companies fell for the week, as ongoing concerns of the “fiscal cliff” weighed on markets during the Christmas week of light trading.

The weighted LABJ Stock Index fell more than 3 percent to close at 133.35 for the week ended Dec. 28. Losers outnumbered gainers 122 to 41, with eight companies unchanged.

The biggest loser was Herbalife Ltd., plunging 13 percent to $29.39. The company was the focus of yet more scrutiny as another big name investor, Whitney Tilson, disclosed his short position in the company’s stock.

Among other big decliners was Green Dot Corp., dropping 8 percent to $12. Reports surfaced recently that the Monrovia company’s prepaid debit cards have been used by scammers to collect fraudulent payments.

The biggest gainer was MRV Communications Inc. Shares of the Chatsworth semiconductor company were up more than 7 percent to $10.95.

Shares of Beverly Hills 3-D technology company RealD Inc. gained 6 percent to $11.08 as year-end box office reports came in positive.