German contractor Hochtief A.G., ranked the world’s largest contractor based on revenue outside its home country, is considering a Sept. 16 buyout offer from Madrid-based construction giant Grupo ACS. The Spanish firm, which is Hochtief’s largest shareholder with a nearly 30% stake, has offered $72.70 per share for the remaining shares, valued at $3.5 billion. Hochtief owns two U.S. contractors, Turner Construction Co., New York City, and Flatiron Construction Corp., Longmont, Colo. ACS acquired 25.1% of Hochtief for $1.65 billion in 2007. ACS, which also owns Spanish contractor Dragados, has acquired U.S. contractors Schiavone Construction, John Picone and Pulice.