Ceres Inc. announced Thursday that it raised net proceeds of about $6.4 million from its public offering of shares on Dec. 14. The Thousand Oaks agricultural biotech issued 2.9 million shares of common stock along with 6,460 shares of preferred stock. The preferred stock can be converted into nearly 16.2 million shares of common stock, meaning each share of preferred stock equals 2,500 shares of common stock. However, the preferred stock will pay the same dividends as common stock. In addition, the preferred stock includes a “beneficial ownership blocker,” intended to prevent stockholders from amassing a significant percentage of outstanding shares. Proceeds from the offering will be used for general corporate purposes such as working capital. Shares closed up 2 cents or 4 percent to 36 cents on the Nasdaq.