CoStar was founded 1987 and handles more than 1.5 million listings and provides research and analysis on millions of U.S. commercial properties.
Founded in 1995, LoopNet boasts more than 800,000 commercial real estate listings on its site and more than 25 million property records. It went public in 2005.
The Federal Trade Commission must sign onto the deal, first announced in April 2011. Both firms filed a consent order with the FTC.
"The companies are not providing details of the consent order pending this commission review and approval. CoStar believes the proposed consent order will not affect its ability to realize the material benefits of the merger," according to the CoStar filing.