The Los Angeles Business Journal’s index of largest local public companies closed up slightly for the week as the broader markets continued a summer rally.

The weighted LABJ Stock Index rose 0.47 percent to 137.86 for the week ended Aug. 17. Gainers outpaced decliners 117 to 55, with four companies unchanged.

One of the biggest local gainers was Physicians Formula Holdings Inc., which jumped 25 percent to $4.30. The Azusa mass-market cosmetics company said that its board had agreed to a buyout offer from a San Francisco private equity firm.

Reed’s Inc. gained 19 percent to close at $5.78. The Los Angeles specialty soda maker reported a better-than-expected second quarter on higher sales and expanded distributorships.

Overhill Farms Inc. rose 13 percent to $4.55. The Vernon maker of frozen food products said it hired an investment bank to evaluate potential sale opportunities.

One of the biggest decliners was Cereplast Inc., which dropped 29 percent to 20 cents. The El Segundo bioplastics maker reported a net loss in the second quarter that was 62 percent larger than the same quarter last year.

Arrowhead Research Corp. fell 17 percent to $2.75. The Pasadena biotech holding company said it entered a securities purchase agreement with institutional and individual investors, with gross proceeds of $6.2 million.

Qualstar Corp. fell 7 percent to $1.70. The Simi Valley maker of automated data storage tape drives reported a disappointing fiscal fourth quarter on lower sales and higher costs related to a proxy battle.