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

The weighted LABJ Stock Index rose less than 1 percent to 188.43 for the trading week ended Feb. 21. Gainers outpaced decliners 87 to 66, with eight companies unchanged.

The biggest gainer was Xencor Inc., jumping 22 percent to $11.05. The Monrovia biotech, which is developing drugs to treat cancer, autoimmune and allergic diseases, did not release any market-moving news.

United Online Inc. gained 21 percent to $12.55. The Woodland Hills Internet service provider reported better-than-expected fourth quarter revenue.

Capstone Turbine Corp. rose 14 percent to $1.77. Analysts at FBR Capital upgraded shares of the Chatsworth maker of micro-turbines.

Among the biggest decliners was Qualstar Corp. The Simi Valley maker of data storage and power supplies this week fell 12 percent to $1.37.

Ducommun Inc. fell nearly 12 percent to $25.37. The Carson aerospace engineering firm reported losses on contracts with two major airplane manufacturers.