Engineering firm Balfour Beatty has revealed it examining the possibility of making an offer for rival Mowlem.
Balfour Beatty reported a strong profits rise during the summer
Last week Mowlem agreed a £290m ($506m) takeover offer from construction firm Carillion, which called the potential deal an "excellent strategic fit".
Now Balfour Beatty, which has building, engineering and rail divisions, said "it is considering making an offer".
"There is no certainty that an offer will be forthcoming," the company added in its statement.
Carillion's agreed deal to buy its smaller rival Mowlem is set to create one of the UK's largest support services and construction firms - with a combined turnover of more than £4.1bn.
Carillion was spun out of the Tarmac demerger in 1999, and has been selling off its traditional contracting businesses to focus on PFI projects.
In August, Balfour Beatty reported a 37% rise in half-year profits after "satisfactory" performances by most of its businesses.
The UK construction and engineering group made pre-tax, post-exceptional profits of £67m in the six months to 2 July.
Since then it has been fined £10m for its role in the Hatfield rail disaster in autumn 2000, when it was the firm in charge of track inspection.