Dice Holdings Inc. this morning announced a public offering of 10 million shares of common stock. The New York City-based provider of career websites, which has its primary operations in Urbandale, said it will use the proceeds to purchase an equal number of common shares from current and former senior management and board members. The majority of the shares sold are being offered by certain shareholders, including affiliates of General Atlantic LLC, Quadrangle Group LLC and a member of Dice Holdings’ board of directors, while the remainder is being offered by the company. In the offering, certain of the selling stockholders have granted to the underwriters an option to purchase up to 1.5 million additional shares.