Transocean shares jumped 5.9% to $5.71 on heavy volume, extending a 26.8% four-week gain as investors responded to the merger announcement.

The company unveiled a $5.8 billion all-stock takeover of Valaris, adding drillships, semisubmersibles and jackup rigs to its fleet.

The combined entity’s drilling backlog will reach about $10 billion with estimated annual synergies around $200 million, improving long-term cash flow visibility.