Marlin Bidco, the buyout vehicle set up by BC Partners and Pollen Street Partners, said that as of Thursday afternoon it had received valid support for its offer from other Shawbrook shareholders owning a combined 7.75 percent of the company.

Shawbrook this month rejected a raised and final 868 million pound offer from the private equity groups, which already hold 38.8 percent.

The offer will now remain open until Monday.

The consortium first made a bid for Shawbrook in January, offering 307 pence per share, before raising its offer to 330 pence in March. However, so far Shawbrook's directors have advised shareholders to reject the offer.

(Reporting by Noor Zainab Hussain in Bengaluru; Editing by Susan Fenton)