If the government continues providing funds for the subsidies, insurers will have “a small profit,” said Craig Wright, the chief actuary at the Florida Office of Insurance Regulation. “If the subsidies are not funded, carriers would face the prospect of large financial losses, which could increase the risk to their solvency.”

“It could be very damaging,” Mr. Wright said. “Our market wouldn’t recover.”

With no guidance or clarity from the Trump administration, state officials are agonizing over what to do. Many expressed a sense of urgency, saying they needed to make decisions soon on rates to be charged in 2018.

Trump administration officials were invited to speak to state insurance regulators and were listed in the program for at least one public session, but they did not show up at that event to provide the promised update on federal policy.

“Most of us are hoping and praying that this gets resolved,” said David Shea, a health actuary at the Virginia Bureau of Insurance. “But that’s not the case right now.”

Without the federal subsidies, insurers would need to get the money — estimated at $7 billion to $10 billion next year — from another source. And that means higher premiums, state officials said.