The Los Angeles Business Journal’s index of largest local public companies fell slightly for the week.

The weighted LABJ Stock Index fell 1 percent to 158.12 for the trading week ending April 19. Decliners outpaced gainers 124 to 40, with seven companies unchanged.

One of the biggest gainers was Virtual Piggy Inc., jumping 19 percent to $2.14. The Los Angeles e-commerce company said it expanded its board to add three independent directors with broad software industry knowledge and experience.

Kythera Biopharmaceuticals Inc. gained 9.5 percent to $22.50. The Calabasas biotech reported promising clinical trial results for its experimental injectable treatment to reduce chin fat.

Puma Biotechnology Inc. rose nearly 8 percent to $34.43. Industry blogs reported that a number of hedge funds were accumulating shares of the West. L.A. cancer treatment developer.

Among the largest decliners was Joe's Jeans Inc., which fell 22 percent to $1.56. The Los Angeles apparel company moved from a profit to a loss in the first quarter on higher operating expenses.

Ceres Inc. fell more than 14 percent to $2.60. Investors continued to react to a disappointing fiscal second quarter for the Thousand Oaks developer of genetically modified feedstocks for renewable energy production