AIG 1973–1994 At the age of 26 in 1973, shortly after completing his military service, Duperreault was hired at
AIG as an actuary. AIG at the time was a midsize property-casualty insurer, and was in the early stages of its transformation by CEO
Maurice R. "Hank" Greenberg into one of the world's largest financial-services firms. senior vice president of AIG subsidiary American Home Assurance from 1981 through 1988, and chief casualty officer from 1985 through 1987. He became one of AIG's most senior executives. From 1989 until 1991 he was CEO of AIG affiliates in Japan and Korea. From 1991 to April 1994 he was president of American International Underwriters, AIG's overseas property-casualty insurance unit. In June 1993 while still president of American International Underwriters he was concurrently named to the additional position of executive vice president of AIG's Foreign General Insurance, He was long considered by industry colleagues and Wall Street analysts to be a potential successor to Greenberg, but Greenberg showed no signs of retiring, and after 21 years at AIG, Duperreault resigned in September 1994 to head ACE Limited, one of AIG's competitors.
ACE Limited In October 1994 Duperreault became the chairman, president, and CEO of
ACE Limited, which at the time was a boutique specialty insurance company based in Bermuda with 50 employees. He greatly expanded and diversified the company, particularly via targeted acquisitions. In 1998 he led the acquisitions of Tarquin plc, CAT Limited, and Westchester Specialty Group. In 2001 Duperreault restructured ACE's operations into two main groups, ACE U.S and Bermuda, and ACE International, with each group headed by its own chief executive. In 2002 ACE partnered with and acquired the largest stake in Huatai Insurance Company of China, allowing both companies to jointly develop new products and services for delivery nationally in China. Having transformed ACE from a niche boutique Bermuda-based insurer to a major global multi-line insurer and reinsurer with more than 9,000 employees operating in 50 countries, Duperreault's leadership of ACE for 10 years has been credited as instrumental in transforming Bermuda from an island nation with a small, reinsurance-focused market into a global insurance center. In May 2006 Duperreault retired, becoming non-executive chairman of ACE.
Marsh & McLennan Companies Two years after retiring in 2006, upon request Duperreault came out of retirement in January 2008 to be president and CEO of the New York-based global firm
Marsh & McLennan Companies (MMC), one of the world's two largest
insurance brokerages, which had helped found ACE Limited in 1985 and which was one of AIG's broker partners. The company was in the midst of a serious crisis, suffering heavy outflows from a bid-rigging scandal in 2004 that cost an initial $850 million settlement in 2005, plus additional substantial annual costs and a prohibition on contingent commissions. Due to that 2004-2005
insurance probe by New York Attorney General
Eliot Spitzer, which alleged MMC had falsified and rigged bids on contracts and favored insurers at the expense of clients in return for higher commissions, the company had also sustained reputational and morale damage, lost business, and talent loss. He also quickly built a strong new executive management team at the corporate and operating levels, implemented greater expense discipline across the company, and evaluated the overall business for fit and synergy. After incrementally selling off some of Kroll's divisions over a two-year period, and grew it substantially via acquisitions. In 2011 he was named to the
U.S. Treasury's inaugural Federal Advisory Committee on Insurance, and in 2012 he was named its first chairman. After five years as president and CEO of Marsh & McLennan Companies, Duperreault retired on December 31, 2012. He had also established a long-term strategy as a foundation for continued success after his departure. He came out of retirement a second time to co-found Hamilton Insurance Group in December 2013 with the principals of Two Sigma, and to be its CEO. with Duperreault as CEO. In January 2014
Sanford I. Weill, the former head of
Citigroup, was hired as the Chairman of Hamilton Insurance Group and Hamilton Re. Needing a balance of insurance and reinsurance, renamed Hamilton at Lloyd's. Hamilton became a Bermuda-based holding company of property and casualty insurance and reinsurance operations in Bermuda, the U.S., and the UK. In late 2016, Hamilton Insurance Group partnered with AIG and Two Sigma to create Attune, a data-enabled, algorithm-driven company that sells commercial insurance online to small and medium-sized businesses,
CEO and Executive Chairman of AIG 2017 -2021 In May 2017, Duperreault was hired as CEO of AIG, Since late 2008 the AIG conglomerate had sold off many of its businesses to pay off the $185 billion U.S. government bailout it received during the
2008 financial crisis. AIG entered into a strategic reinsurance partnership with Hamilton Re; He also curtailed the practice of
share buybacks, asserting that a better use of capital was acquisition of smaller companies. Four months later Duperreault acquired Bermuda-based Validus Holdings Ltd. The deal also brought in fresh underwriting talent, particularly in property risk and catastrophe risk. He recruited or promoted more than a dozen top-tier senior executives and 125 senior underwriters to help execute his vision; this new management team included his former colleague
Peter Zaffino of Marsh & McLennan Companies, whom Duperreault hired as executive vice president and global chief operating officer and also CEO of AIG's General Insurance business. He also instituted plans to cut costs and to exploit scale in dealing with suppliers and property expenses. In February 2019 Duperreault noted that before his arrival as CEO a company-wide "go large" strategy at AIG had created out-sized risk, volatility, and losses, often exacerbated by multi-year contracts. In June 2019 the company formed AIG Re, which consolidated its reinsurance operations, including Validus Re, AlphaCat, and Talbot Treaty, into one global business. In August 2019 AIG reported its second consecutive quarter of underwriting profits. Also in August 2019, Duperreault and Zaffino announced "AIG 200", a three-year company-wide program to improve its operational processes and infrastructure and substantially lower its expenses, by shedding legacy processes and excess manual interventions, modernizing and digitizing workflows, and unifying the company's operations. On 1 January, 2020, Zaffino succeeded Duperreault as AIG president. Then on March 1, 2021, Zaffino succeeded Duperreault as AIG's CEO, with Duperreault becoming executive chairman of the board.
Executive Chairman of Cedar Trace Limited Cedar Trace Limited is the holding company of the re/insurance platform Mereo Insurance. Launched in early 2025, Duperreault is the co-founder along with insurance industry veterans David Croom-Johnson and Richard Holden. The Bermuda-based company, which is licensed by the Bermuda Monetary Authority and holds an "A-" credit rating from AM Best, writes property, casualty and specialty insurance. ==Memberships==