Builder Carillion may make a third attempt to buy rival Balfour Beatty after having its first two bids rejected in a spat over a subsidiary, broker Brewin Dolphin says.Balfour on Monday rejected a second bid from Carillion after the latter revised its first approach, in which it wanted Balfour to drop its plan to sell US engineering consultancy Parsons Brinckerhoff.Carillion offered to revise its terms, but Balfour said the deal was too risky.Brewin said it would not be surprised if Carillion announced a further attempt to bring the two sides back together at its results next week.Analyst Stephen Williams said: "We suspect Carillion could well go hostile."The tone of the Carillion statement recently seemed to be one of anger that the talks had been terminated but Balfour Beatty is now open to an external bid and there is substantial value to be unlocked."We are not convinced that remaining independent is a viable option."Shares in Balfour rose 6.6p or 2.8% to 243.8p at 14:53 in London, while Carillion's stock increased 2.2p or 0.7% to 322.9p.PW