Wimpey's price has increased slightly since the announcement from 195p to 202p. McAlpine's has jumped 57p to 395p, with investors eying the higher rating and extra cash the deal would bring.
Meanwhile, Amey's mini-recovery stalled when its share price fell 11p (3.4%) from 322p to 311p.
There is concern about results at Balfour Beatty next week, with analysts waiting to see how the company deals with the fallout from the Hatfield crash, lower rail margins, and problems with projects in Turkey and Africa.