The Trump administration and Republicans in Congress face a tough balancing act when it comes to repealing Obamacare.
They have to make sure they don't upend the Affordable Care Act too quickly, so that they don't cause the exchange market to collapse. At the same time, they can't delay a replacement plan for too long.
"Insurers have only a matter of weeks before they have to file rates and plans for participation in 2018," said Sabrina Corlette, a research professor at Georgetown University's Center on Health Insurance Reforms.
"The longer there's uncertainty, the longer (insurers) don't know what the rules of the road are, the more they're going to have to adjust for that uncertainty," she said.
"When you think about the 20 million people who are covered (under Obamacare) you're going to have to have a bridge from what they have to today to what they will have in the future," former Aetna CEO Ron Williams told CNBC. "Without that you really have no way to accommodate the infrastructure of the program or even the amount of work to be done."