The Los Angeles Business Journal’s index of largest local public companies closed down for the week.

The weighted LABJ Stock Index fell 1.5 percent to 166.62 for the trading week ended May 24. Decliners outpaced gainers 76 to 67, with 26 companies unchanged.

One of the biggest gainers was DTSI Inc., gaining 9.5 percent to $20.67. The Calabasas audio technology company signed a larger deal with Chinese automaker BYD to provide its DTS Digital Surround system in four new BYD models.

Virtual Piggy Inc. rose 8 percent to $2.28. The Hermosa Beach online commerce system for children signed its new partnership deals in the United States and in Great Britain.

Among the largest decliners was Sport Chalet Inc. falling 6 percent to $1.80. The La Canada sporting goods retailer reported better fiscal fourth quarter sales and a smaller loss, but the results still disappointed investors.

MannKind Corp. fell 5 percent to $6.51. Shares of the Valencia biotech company were volatile this week amid online media speculation that the company was a ripe acquisition target.