Rithm Capital, the real estate investment firm looking to seal a deal to acquire Scupltor Capital Management, is sticking with its original offer for the business despite a an improved bid from a rival group led by Saba Capital boss Boaz Weinstein, according to a report by Reuters.

The report cites a regulatory filing made on Thursday as confirming the sweetened offer, with a special committee at Sculptor, the largest US-listed hedge fund firm with around $30bn in assets, reportedly now evaluating the proposal.

According to Sculptor's filing, Rithm is not prepared to increase its original $639m ($11.15 per share) offer to acquire the firm, while Weinstein's group, is reportedly prepared to pay around $13 a share for Sculptor having initially bid $12.76.

Weinstein is backed by billionaire investors Bill Ackman who runs Pershing Square Capital Management, Marc Lasry who heads Avenue Capital Group and Jeff Yass who founded Susquehana International Group.