The Los Angeles Business Journal’s index of largest local public companies was nearly flat this week as investors in the broader markets digested mixed earnings reports.

The weighted LABJ Stock Index rose 1 percent to 169.54 for the trading week ended July 26. Gainers outpaced decliners 101 to 55, with eight companies unchanged.

1st Century Bancshares Inc., the Century City holding company for 1st Century Bank, jumped nearly 18 percent to $7.35. Los Angeles biotech testing company Response Genetics Inc., which gained 13 percent last week after announcing the renewal of a contract with a large customer, rose another 16 percent this week to close at $2.09. MRV Communications Inc., a Chatsworth maker of optical communications network equipment, rose more than 13 percent to $10.20.

Also, Arrowhead Research Corp. gained 13 percent to $3.07 after the Pasadena biotech announced the start of early stage clinical trials for an experimental treatment for chronic hepatitis B virus infection.

Activision Blizzard Inc. jumped 15 percent to $17.46 on Friday, up 12 percent for the week, after the Santa Monica video game developer announced a plan to buy out most of Vivendi SA’s stake in the company.

Among the biggest decliners was Santa Monica Spanish-language media company Entravision Communications Corp. which ended the week down 21 percent to $5.26. That prompted investment analysts at Wedbush on Thursday to raise their 12-month price target on the stock from $4.25 to $5.75.

Malibu toymaker Jakks Pacific Inc. fell nearly 13 percent to $6.11 after reporting a big second-quarter loss.