Activist investor Carl Icahn has raised his stake in American International Group Inc by 5.2 percent, putting him in a better position to pressure the insurer to split into three independent companies.

Icahn now owns 44.4 million shares in AIG, a regulatory filing showed on Monday, bringing his stake in the biggest U.S. commercial insurer by premiums to about 4 percent, according to Thomson Reuters data.

Tensions have been mounting between AIG Chief Executive Peter Hancock and Icahn over the billionaire’s suggestion in October that the company should break up – an idea Hancock promptly rebuffed.

Icahn had argued that a split would help AIG rid itself of the regulatory burden of being a systemically important financial institution, which requires higher capital cushions.

In February, the insurer agreed to add Samuel Merksamer, a managing director at Icahn Capital LP, to its board.

AIG continues to focus on staying the course. The insurer is committed to retaining operations in both life insurance and property-casualty coverage, Bloomberg reported Chairman Doug Steenland as saying at the insurer’s May 11 annual meetings in New York.

“We remain of the view that that is the right long-term position for AIG,” Steenland said. “Although, the specific components of what’s in each of those businesses may change.”

*Additional Bloomberg archive material was added to this story.