The Los Angeles Business Journal’s index of largest local public companies rose for the week ended May 20 as investors reacted to concerns that U.S. consumer demand may be weakening.

The weighted LABJ index closed down 0.79 percent to 128.66, with decliners outpacing gainers 122 to 49.

Poor quarterly reports drove the biggest decliners. Bidz.com Inc. dropped 19 percent to $1.05. The Culver City online jewelry retailer reported disappointing quarterly earnings.

Tutor Perini Corp. fell 13 percent to $19.85. The Sylmar construction company continued to feel pressure from its lack-luster first quarter earnings and declining revenue.

Van Nuys semiconductor maker Trio Tech International dropped 10 percent to $3.72, also after reporting a revenue decline in its first quarter.

Boingo Wireless Inc. the Los Angeles Wi-Fi hotspot operator whose stock has disappointed since its May 4 initial public offering, fell another 17 percent to $9.71, despite announcing a large installation contract with Los Angeles mall developer Caruso Affiliated.

Among the largest gainers was Reed’s Inc., which rose 11 percent to $2.13. The Los Angeles natural soda maker reported better-than-expected first quarter earnings.

L.A. clean energy provider Rentech Inc. rebounded from news that its renewable energy center loan had been put on hold by the U.S. Department of Energy when it announced the acquisition of a clean fuel company. Shares rose 6.5 percent to 99 cents.