The Los Angeles Business Journal’s index of largest local public companies closed up the week amid speculation about further economic stimulus from the Federal Reserve might be forthcoming.

The weighted LABJ Stock Index closed up 2.7 percent to 136.77 for the week ended July 27. Decliners outpaced gainers 84 to 79, with 12 companies unchanged.

The biggest mover was Green Dot Corp., which plunged 62 percent to $9.06. The Monrovia prepaid debit card provider provided a weak annual profit outlook amid sharper competition and higher costs, prompting 10 analysts to downgrade the stock.

Shares of several other local companies declined after disappointing quarterly reports or profit warnings.

Staar Surgical Co., a Monrovia maker of implantable contact lenses, dropped 29 percent to $5.72 after saying it expects second-quarter earnings to fall short of analyst estimates.

VCA Antech Inc. slid 16 percent to $18.09 after its second quarter results fell short of expectations. The Los Angeles operator of veterinary hospitals also cut its outlook for the year.

Stamps.com Inc. fell 15 percent to $21.34. The Los Angeles online postal service reported a better-than-expected second quarter but warned that economic headwinds may slow growth.

Among the biggest gainers was MPG Office Trust Inc., which jumped 35 percent to $3.17. The downtown Los Angeles landlord announced that restrictions on selling certain properties would expire in June, sooner than expected, leading to speculation that the REIT might soon put itself on the market.

Dole Food Co. rose 25 percent to $11.06. The Westlake Village producer and distributor of fruits and vegetables continued to benefit from last week’s announcement that it may consider a sale or spinoff of its packaged-foods unit in order to enhance shareholder value.

Ixia Inc. gained 16 percent to $14.96. The Calabasas maker of computer network testing products forecast third-quarter revenue above Wall Street estimates.