(Reuters) — Billionaire investor Carl Icahn has sold his stake in American International Group Inc., ending a more than two-year association with one of the largest U.S. property/casualty insurers, according to a person familiar with the matter.

The activist investor started accumulating AIG shares in 2015 and became its third largest investor with a 4.76% stake as of the end of 2017.

But Mr. Icahn began planning to sell that stake last year as it became evident that AIG would name Brian Duperreault, an industry veteran who would oppose demands to break up the company, as its new CEO, said a second person familiar with the matter.

Both people spoke to Reuters on the condition of anonymity because they were not authorized to discuss the matter publicly.

Mr. Icahn exited AIG when the company's stock changed hands at a price between $60 and $65 -- levels last seen in February, one of the sources said.

At $65 per AIG share, Mr. Icahn's stake would have been worth $2.78 billion, according to Reuters' calculations.

It was not immediately known how much Mr. Icahn made from the AIG investment.

AIG shares fell nearly 1% to $52.30 in morning trade on Monday.

Icahn Enterprises L.C. did not immediately respond to a request for comment and AIG declined to comment.

In the company's first quarter investor presentation released last week, AIG was not included on a list of significant holdings. Its presentation for the fourth quarter of 2017 had shown AIG as the largest of five significant holdings.

In keeping with his aggressive activist investment strategy, Icahn had publicly pressed AIG to shrink and threatened a proxy fight with the company's management.

The insurer was forced to embark on a two-year turnaround plan developed by former CEO Peter Hancock, which intended to return $25 billion to shareholders.

The company also sold some assets and hired Mr. Duperreault, spurring Mr. Icahn to back off on his demand to break up the company.

In March, AIG said Samuel Merksamer, a representative of Mr. Icahn on the company's board, would not seek re-election.

On Wednesday, AIG shareholders will vote on a $43.1 million 2017 compensation package for Mr. Duperreault, who has vowed to grow the company by making acquisitions and boosting revenues.