By the numbers:

• CBO is anticipating a 21% jump in the cost of federal subsidies this year, driven by a 34% jump in premiums for the “benchmark” plans to which those subsidies are pegged.
• But after that, CBO expects a big slowdown. Federal spending on the ACA’s premium subsidies will likely grow by about 5% per year for the rest of the next decade, the budget office said. Those annual increases are mainly a result of rising health care costs.

How it works: Premiums go up every year, and premiums inside the ACA’s marketplaces had seen some very big spikes before Trump was elected. This isn’t entirely on Trump.

• But there’s no question the repeal of the mandate, and his decision to end a separate stream of payments to insurance companies, drove premiums even higher this year, and will have a similar effect next year.

Why it matters: The ACA’s insurance markets are increasingly turning into an option that only really works for the lower-income people who receive premium subsidies. Those payments largely insulate them from skyrocketing premiums, while unsubsidized consumers are finding ACA coverage further out of reach.