Switzerland's Transocean is to buy George Economou-chaired Ocean Rig in a deal worth $2.7bn.
The definitive merger agreement involves a cash and stock transaction and includes restructured Ocean Rig's debt, Transocean said.
It will pay 1.6 new shares plus $12.75 in cash for each Ocean Rig share, valuing the stock at $32.28 - a 20.4% premium to Ocean Rig’s ten-day average share price.