(Reuters) - Billionaire hedge fund manager Daniel Loeb's firm Third Point LLC wants to build a stake in United Technologies Corp UTX.N,

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according to a filing with the Federal Trade Commission, as the U.S. aero parts maker explores a breakup of its businesses.

Loeb’s Third Point Offshore Fund Ltd has requested permission from the U.S. consumer protection regulator to acquire shares in the company above a certain threshold, according to the filing dated March 23 on the FTC’s website.

Shares of Farmington, Connecticut-based United Tech rose as much as 3.6 percent to $126.73 on Monday.

United Tech declined to comment and Third Point was not immediately available for comment.

United Tech, which makes Otis Elevators, Pratt & Whitney aircraft engines and Carrier air conditioners, in February said it would decide by the end of 2018 whether its businesses were more valuable together or better off as separate entities.

Chief Executive Officer Greg Hayes has said if the company were to split, its aerospace business would have about $45 billion to $50 billion in sales, Otis elevators unit about $12 billion to $13 billion, and the climate-control business about $17 billion to $18 billion.

The CEO has indicated that a final review of its businesses was possible after it closes the acquisition of avionics and interiors maker Rockwell Collins Inc COL.N by the third quarter of 2018.

The company’s shares have lagged the broader market under Hayes as the company spent heavily on developing a new fuel-saving geared turbofan aircraft engine and as sales of Otis elevators were pressured by a supply glut in China.

Up to Friday's close, United Tech's shares had fallen about 9.4 percent in the past 12 months, compared with a 13.9 percent increase in the Dow Jones Industrial Average .DJI.

Billionaire investor William Ackman’s Pershing Square Capital Management is also building a position in United Tech, according to reports in February.