Shares of U.K. betting company Entain /zigman2/quotes/207493593/delayed UK:ENT +0.06% tumbled 10% after DraftKings /zigman2/quotes/213120645/composite DKNG +1.92% said it won't make a firm offer. "After several discussions with Entain leadership, DraftKings has decided that it will not make a firm offer for Entain at this time. DraftKings stock shot up 5.6% in morning trading. Based on our vertically-integrated technology stack, best-in-class product and technology capabilities and leading brand, we are highly confident in our ability to maintain a leadership position and achieve our long-term growth plans in the rapidly growing North America market," said DraftKings CEO Jason Robins. The statement bars DraftKings from making an offer for at least six months unless there's another bid. MGM Resorts /zigman2/quotes/209932643/composite MGM +1.26% operates the BetMGM venture in the U.S. with Entain.