It’s been 17 months since activist Carl Icahn started targeting American International Group Inc.’s Chief Executive Officer Peter Hancock, faulting him for the company’s sluggish returns and pressuring him to sell assets. The CEO announced his resignation Thursday after posting losses in four of the past six quarters.

Here are some of the people who may be considered to replace Hancock, based on interviews with executives and advisers across the industry:

Dan Glaser: CEO of Marsh & McLennan Cos.

Why he could be a good fit: He was previously an executive at AIG, working there for seven years through 2007. He still works closely with the insurer because Marsh & McLennan helps connect AIG with clients, and he’s staffed his current company with former AIG colleagues.On the other hand: He’s currently running a $37.7 billion firm, the world’s largest broker.

William Jurgensen: AIG director, ex-CEO of Insurer Nationwide

Why he could be a good fit: He’s one of a few of the insurer’s directors that has experience in the insurance industry. Jurgensen, the former CEO of Nationwide Mutual Insurance Co., is the chairman of AIG’s audit committee, and a member of the risk and capital committee. On the other hand: He’s 65, which is on the older side for a CEO. (The average age for the companies in the S&P 500 Index is 57, according to data compiled by Bloomberg.) He hasn’t led an insurance company since 2009 and he’s never run a publicly traded firm.

Peter Fisher: AIG director

Why he could be a good fit: Fisher was an executive at the Federal Reserve Bank of New York and has also worked for the U.S. Treasury Department, and that experience can prove helpful as AIG faces a changing regulatory environment as a systemically important financial institution. AIG also has more than $320 billion in investments, and Fisher previously was an executive at BlackRock Inc., the world’s largest asset manager. On the other hand: He’s never been CEO of a publicly traded company, or an insurer, which means he doesn’t have the underwriting expertise many have derided Hancock for lacking.

Brian Duperreault: CEO of Hamilton Insurance Group

Why he could be a good fit: He’s one of the industry’s most respected executives, and his current company already has a partnership with AIG in insuring small businesses. He worked at AIG for years, rising to become an executive, then leaving to become CEO of rival Ace Ltd. He then went to lead brokerage Marsh & McLennan during the 2008 financial crisis before leaving in 2012, then starting Hamilton. Elyse Greenspan, an analyst at Wells Fargo & Co., said in a note to clients Thursday that Duperreault could be on the short list of candidates for the role.On the other hand: Hamilton is linked to hedge fund firm Two Sigma Investments, one of the best known quantitative money managers, and his investors have been happy with the partnership. Duperreault, at age 69, may want to end his career at a steadily expanding company instead of AIG, which has been going through years of restructuring.

Rob Schimek: CEO of AIG’s commercial unit

Why he could be a good fit: Schimek has been working side by side with Hancock on AIG’s restructuring over the past few years, striking reinsurance deals with Swiss Re AG and Berkshire Hathaway Inc. in which AIG will still be responsible for handling claims for clients. Schimek could help provide a sense of continuity. On the other hand: AIG’s commercial unit has had a host of problems. The business has posted several billions of dollars of losses to cover reserves as claims swelled, and leadership had to tweak financial targets.

Peter Zaffino: CEO of Marsh Inc.

Why he could be a good fit: As the head of the brokerage division of Marsh & McLennan, he’s already working with many of AIG’s largest clients. Zaffino had worked closely with Duperreault at MMC, and Duperreault could be named chairman.On the other hand: He doesn’t have underwriting expertise, a part of the business that AIG has been struggling to adjust.

Robert S. Miller: AIG director

Why he could be a good fit: He was the insurer’s chairman through some of its toughest times, joining the board in 2009 and leading it starting in 2010. He was instrumental in helping to repay a U.S. government bailout that swelled to more than $182 billion. Miller stepped down as chairman in 2015 but is still a part of its technology committee and nominating and corporate-governance committee. Miller is CEO of International Automotive Components Group SA.On the other hand: He currently runs another firm, and also hasn’t led an insurance company.

Doug Steenland: AIG chairman

Why he could be a good fit: Steenland became AIG’s chairman in 2015 and was critical in helping Hancock create a new strategy for the firm, including billions of dollars in asset sales and cost cuts, both of which won applause from activist investors. On the other hand: His background is in the airline industry. At 65, Steenland is also above the average age for CEOs in the S&P 500.

The executives or their representatives either declined to comment or didn’t return calls or emails. AIG also declined to comment.