Former Citigroup Chairman and Chief Executive Sanford I. “Sandy”Weill will serve as chairman of Hamilton Insurance Group, Ltd.,which recently purchased SAC Re and renamed it Hamilton Re.

Former Marsh & McLennan Companies CEO Brian Duperreaultled the group of investors that purchased SAC Re last monthfrom billionaire trader Steven A. Cohen's SAC Capital Advisors andrebranded it.

SAC pleaded guilty in November to insider trading, acceptingresponsibility for criminal behavior by at least six of itsemployees, according to Reuters.

Duperreault became CEO of Hamilton Re.

Duperreault says of Weill's appointment, “Sandy Weill is an iconin the financial-services sector; someone who has been at theforefront of change throughout his career. Under his leadership,and with our forward-thinking management team, I have no doubt thatour goal of establishing a leading insurance and reinsurancebusiness will be realized. It's an honor to serve with Sandy.”

Weill says, “I think it is rare to have an opportunity to beinvolved with people who have an exemplary record in what isnecessary to run a successful insurance company. Brian Duperreaulthas run businesses very successfully in all parts of the insuranceindustry from Marsh & McLennan, to the ACE Group in Bermuda, aswell as his long stint at AIG.

“Brian's teaming up with Two Sigma marries insurance expertisewith an outstanding record of investment expertise, a combinationthat I believe will work well together, and I look forward toworking with the board on the opportunities and challenges that lieahead.”

According to an Academy of Achievement biography,Weill created Citigroup through the 1998 merger of Citicorp andTravelers Group. The deal faced a legal obstacle: the 1933 GlassSteagall Act, which prevented commercial banks from gettinginvolved in investment banking.

A July 2012 CNNMoney article states that Weill helped lobby in 1999 for therepeal of the act.

But the article notes that Weill, who stepped aside asCitigroup's CEO in 2003 and retired as chairman in 2006, told CNBCin 2012 that he believed a firewall between commercial andinvestment banks is needed.

“What we should probably do is go and split up investmentbanking from banking,” Weill told CNBC. “Have banks do somethingthat's not going to risk the taxpayer dollars; that's not too bigto fail.”