The year-long inquiry into hospitals managed by Apollo Global Management and Leonard Green & Partners comes amid growing calls for increased oversight of private equity in healthcare.

A U.S. Senate committee accused private-equity healthcare investors of choosing profits over patient care, adding a prominent voice to those claiming Wall Street is putting the medical system at risk.

Private equity investors in the health-care industry will face additional oversight in Massachusetts under a new law that Governor Maura Healey plans to sign on Wednesday.

The bill’s passage is a rare success in a nationwide effort to crack down on private equity firms after a string of high-profile healthcare bankruptcies.