Haitong Securities Co, one of China's three publicly traded brokers, said shareholders approved a plan to quadruple its capital to help expand into investment banking and compete with overseas brokerages.

The Shanghai-based company said it will sell 1 billion new shares for at least 13.15 yuan each to no more than 10 institutional investors, including mutual funds, brokers, asset managers and insurers. Shares investors use to trade Haitong plunged yesterday by their 10 percent limit on the Shanghai exchange to 41.37 yuan.

Haitong is now traded under the name of Shanghai Urban Agro-Business Co, the publicly traded company taken over last month in a so-called backdoor listing. The broker's plan to rename Shanghai Urban as Haitong is still pending the approval of the securities regulator.