Billionaire activist investor Carl Icahn renewed his call Tuesday to break up American International Group Inc., once again berating the insurance giant’s chief executive, Peter Hancock, for not doing enough to maximize shareholder returns. Icahn is AIG’s largest investor and has disputed AIG’s strategy of selling assets rather than breaking off large parts of its operations.

“It is abundantly clear to me there is only one sensible path for AIG to follow: become a smaller, simpler company,” Icahn said in a letter to AIG’s board of directors. The renewed call comes a week after MetLife Inc., the largest U.S. insurer, announced it plans to spin off a large part of its U.S. retail business into a separate, publicly listed company to reduce regulatory scrutiny.

Institutions like MetLife and AIG have been deemed by U.S. regulators as systemically important financial institutions (SIFIs). In the wake of the 2007-09 financial crisis, SIFIs have been required to hold more cash in reserve because of the threat they pose to the U.S. economy if they collapse. Icahn is concerned about the “enhanced regulations” AIG faces as a SIFI. He called on AIG to sell off units and focus on its core strength in property casualty coverage.

In October the 79-year-old business magnate publicly admonished Hancock for mismanagement and demanded he begin the process of breaking AIG into three companies, Bloomberg reported. He’s also threatened to rally shareholders to his cause of seeking Hancock’s replacement.

Hancock has sold some underperforming units, such as operations in Central America and Taiwan, but Icahn has dismissed the strategy of selling off small assets in lieu of a more aggressive breakup strategy. Icahn is beating his drums ahead of AIG’s Jan. 26 annual presentation to investors in which the company will outline its business strategy.

American International Group Inc. (NYSE:AIG) shares jumped 1.7 percent to $57.03 Tuesday after the news of Icahn's statement broke. The company’s share price is up nearly 12 percent over the past 12 months. AIG pays a quarterly dividend, which was increased in September 2015 to 28 cents per share from 13 cents.