The Los Angeles Business Journal’s index of largest local public companies closed down for the week ended June 10 as investors reacted to indications that the economy is slowing.

The weighted LABJ index fell 2.6 percent to 123.27, with decliners outpacing gainers 123 to 38 and 21 companies unchanged.

Among the biggest decliners was Boingo Wireless Inc., which went public last month. Shares of the L.A. company fell 25 percent to $7.65 after the Santa Monica Wi-Fi provider reported a wider first quarter loss.

Beverly Hills 3-D cinema technology company RealD Inc. continued to take a beating on continued concerns about consumer resistance to paying more to see 3-D versions of films. Shares dropped nearly 21 percent to $20.90.

ReachLocal Inc., a Woodland Hills online marketing company for small to mid-sized businesses, slid nearly 14.5 percent to $16.30 on concerns about increased competition in its sector.

Skechers U.S.A. Inc. declined 14 percent to $13.75, after the Manhattan Beach footwear maker’s appearance at an analysts’ conference.

Among a handful of significant gainers was Response Genetics Inc., a Los Angeles developer of cancer diagnostic tests. Shares jumped 25.5 percent to $2.95 despite a lack of market-moving news.

Radnet Inc., a Los Angeles-based operator of medical diagnostic imaging centers, rose 10 percent to $4.89 following a presentation at an investor conference