If the New York State Department of Financial Services has anything to do with it, the planned merger between CVS Health and Aetna Inc. may not be a done deal.

At a public hearing on Thursday, the agency’s superintendent, Maria Vullo, said she is concerned that CVS, which had to borrow $40 billion to fund the $69 billion deal, could raise insurance premiums for millions of residents, according to a New York Post account of the hearing.