The former chairman of the one-time biggest banking and financial services group in the world is to become chairman of a new Bermuda-based reinsurer, it was revealed yesterday.

Sandy Weill, who retired as chairman of US-based Citigroup in 2006, will head the board of directors at Hamilton Insurance Group, formed by Island industry tycoon Brian Duperreault and the holding company for the new Hamilton Re.

Mr Duperreault said: “Sandy Weill is an icon in the financial services sector, someone who has been at the forefront of change throughout his career.

“Under his leadership and with our forward-thinking management team I have no doubt that our goal of establishing a leading insurance and reinsurance business will be realised. It’s an honour to serve with Sandy.”

Mr Duperreault formed Hamilton Insurance Group last month in partnership with New York-based Two Sigma Investments, which will manage Hamilton Re’s assets.

Mr Weill, 80, was instrumental in the 1997 merger of his Travelers Group with Citicorp, the parent company of Citibank, to create Citigroup.

At the time, Citicorp was the world’s largest supplier of credit cards, and Citibank was the second largest bank in the United States.

On the morning the planned merger was announced, the two companies were valued at about $70.6 billion. By the end of the day, the value of their combined stock had jumped to $83.6 billion.

Mr Weill, 80, said: “I think it is rare to have an opportunity to be involved with people who have an exemplary record in what is necessary to run a successful insurance company.

“Brian Duperreault has run businesses very successfully in all parts of the insurance industry, from Marsh & McLennan, to the Ace Group in Bermuda, as well as his long stint at AIG.

“Brian’s teaming up with Two Sigma marries insurance expertise with an outstanding record of investment expertise, a combination that I believe will work well together and I look forward to working with the board on the opportunities and challenges that lie ahead.”

Hamilton Insurance Group had around $800 million in capitalisation at the end of last year, while Hamilton Re, a property and casualty reinsurer, is rated A- (excellent) and stable by ratings agency AM Best.