The Los Angeles Business Journal’s index of the 200 largest local public companies eked out only a slight gain for the week ended August 21, despite a Friday market rally after Fed Chairman Ben Bernanke said the economy is on the verge of recovery.

The weighted LABJ index closed up 0.59 percent, 104.41, with gainers outpacing decliners 98 to 85.

Los Angeles synthetic fuels developer Rentech Inc. was among the top gainers, adding 75 percent to close at $2.16 after announcing two major sales of its synthetic diesel, which from green waste and natural gas.

Most other gainers saw significantly smaller rises in price. Carpinteria fast food chain operator CKE Restaurants Inc. added 11 percent to $10.05 after reporting a smaller drop in four-week same-store sales at its Carl’s Jr. and Hardee’s restaurants than the month earlier,

Los Angeles managed care and hospital operator Prospect Medical Holdings, Inc. rose 10 percent to $4.20 after reporting a better-than-expected net loss in its second quarter.

Among companies showing the largest declines, Agoura Hills video game developer THQ Inc., which dropped 13 percent to $5.71 on reports of a share sharp industry wide drop in July game sales.

Online horse race betting company Youbet.com Inc. ended the week down 6 percent to $2.41 following an analyst downgrade.