CoStar Group Acquires UK's largest commercial property marketplace Realla PR Newswire LONDON, Oct. 12, 2018 LONDON, Oct. 12, 2018 /PRNewswire/ -- CoStar Group, the leading global provider of commercial real estate information, analytics and online marketplaces has announced its acquisition of Realla, the UK's largest public portal specialised in commercial property. CoStar is the world leader in operating digital CRE marketplaces, and attracts 40 million unique visitors a month across its North American and European websites. The CoStar network includes LoopNet.com, the number one commercial property marketplace and Apartments.com, the number one apartment marketing site.