May 15 (Reuters) - Arm Holdings is facing an antitrust probe by the U.S. Federal Trade Commission over the British chip designer's licensing of its semiconductor technology, part of ongoing global scrutiny of the business, Bloomberg News reported on Friday.

The FTC is investigating whether Arm is trying to illegally monopolize parts of the semiconductor market. It is looking to assess if Arm will reject or downgrade the licensing agreements for its chip blueprints used to design central processing units, the report said, citing people familiar with the matter.

Earlier this year, the US regulator notified Arm of the investigation and demanded the company preserve documents, according to Bloomberg.

A big portion of Arm's revenue comes from licensing its technology to companies such as Nvidia and Apple and collecting royalty payments on design use.

Reuters was not able to verify the report. Both Arm and the FTC did not immediately respond to Reuters requests for comment.

Regulators outside the U.S. are also probing Arm's practices.

South Korea's antitrust regulator was investigating the Seoul offices of Arm in November, as part of ongoing scrutiny of the company's licensing practices.