James Schiro questions rival suitors' ability to extract value from deal.
Zurich global chief executive, James Schiro, has declared his company is best placed to buy RBSI's £7bn insurance assets.
Bloomberg reported that Schiro, who was speaking yesterday in New York, said that Zurich was the only one of four possible buyers - the others being Allianz, Travellers and Allstate - that would be able to create sufficient synergies from the deal.
"To extract value in that business, we're the only direct player who can do it," he said.
"We probably have the greatest synergies for an asset like that.''
Allstate, which is the largest listed home and auto insurer in the US, has repeatedly been linked with bids for RBSI's insurance assets, which control £5bn premiums in the UK, and a third of the UK private motor market.
Allstate has no insurance operations outside the US. The company's market cap is considerably smaller than Zurich, standing at $27.6bn and $39.6bn, respectively.
Bloomberg said that given the weakness of the dollar, an acquisition in Europe would prove difficult for the American players.
RBSI's UK business, which includes Direct Line, Chirchill and NIG, made profits of £683m last year.
RBS needs to raise £5bn in tier-one debt to shore up its balance sheet, equating to around £7bn in capital.
This week, it raised £12.3bn pounds via its shareholders.
RBS chief Sir Fred Goodwin said earlier this week that he expected to receive the full price for RBSI despite suggestions by analysts that the exit of a number of suitors, including Berkshire Hathaway, Generali, AIG and Ping An, would drive the asking price down.
Goodwin told reporters on Wednesday it would be some time before any deal would be completed. "I would not be holding my breath," he said.
Schiro would not confirm whether Zurich had tabled a bid for the business.
