March 18 (Reuters) - Occupational health services provider Concentra Group, a unit of healthcare company Select Medical Holdings, said on Monday it has confidentially filed for an initial public offering (IPO) in the United States.

The number of shares to be offered and the price range for the proposed offering have not yet been determined, Concentra said.

Earlier this year, Select Medical had announced its plan to pursue the separation of Concentra, aiming to create two independent, publicly traded companies. The process is expected to be completed in late 2024.

The potential offering would add to the growing number of healthcare firms looking to list amid a stuttering rebound in the IPO market in the United States.

Healthcare provider PACS Group last week filed its paperwork to go public in the U.S., while Peruvian firm Auna is set to list on the New York Stock Exchange this week.

Private equity firm KKR-backed BrightSpring Health Services also went public in January.

Founded in 1979, Concentra provides occupational medicine, urgent care, physical therapy, drug screening and physical exams in the United States.

The company operates 544 occupational health centers and 150 onsite clinics at employer worksites throughout 42 states, apart from providing telemedicine for work-related illnesses and injuries.

Concentra was previously owned by health insurer Humana , which sold it in 2015 for about $1.06 billion to a joint venture between Select Medical and private equity firm Welsh, Carson, Anderson & Stowe.

Select Medical boosted its ownership in Concentra to 100% in 2021. (Reporting by Arasu Kannagi Basil in Bengaluru; Editing by Shilpi Majumdar)