Oslo-listed Subsea 7 is making a $2bn offer for 100% of US oil and gas contractor McDermott International.

The Kristian Siem-backed OSV owner and contractor will pay $7 per share, against its previous closing price of $6.05, a 16% premium.

This will be payable either in cash or up to 50% in Subsea 7 stock and the rest in cash, if the McDermott board agrees.