CoStar Group Inc. shares CSGP, -3.68% slid 2.3% in premarket trade Wednesday, after the provider of online real estate marketplaces, information and analytics said it’s issuing $750 million of common stock as it joins the S&P 500 index. The company said it expects the offering to represent just a portion of the expected index fund demand for its stock once it’s added to the index before the open of trade on Sep. 19. Proceeds of the offering will be used to fund all or part of the costs of any strategic acquisition the company may agree to in the future, as well for working capital and other general corporate purposes. Goldman Sachs and JP Morgan are underwriting the offering. Shares are down 3% in the year to date, while the S&P 500 SPX, -0.24% has fallen 17%.
