Today is the last day for people in most of the country to sign up for coverage through the Affordable Care Act.


Note: Data includes partial weeks. The 2018 open enrollment window is Nov. 1 to Dec. 15, 2017. The 2017 window was Nov. 1, 2016 to Jan. 31, 2017; Data: Centers for Medicare & Medicaid Services; Chart: Chris Canipe / Axios
The final results from this signup period will help insurance companies figure out whether their outlook for the future is terrible, or merely bad.Be smart: Insurers are already beginning to look ahead to 2019 — and they're seeing a policy landscape that leads directly to higher premiums, if not to giving up altogether on some of the ACA's exchanges. It's impossible for ACA enrollment to make that outlook much better, but a disappointing number this year could make things even worse.
Where it stands: Enrollment ends today in the vast majority of the country. A few state-run exchanges, including New York and California, have extended enrollment into January.
- The number of sign-ups is surging right now, as the deadline approaches. But it was already so far behind that this year's totals are highly unlikely to match last year's.
- Enrollment is supposed to be going up. When it goes down, that's bad. And it's probably going to go down.
What's next: Beginning in the spring, insurers will start to take stock of their customer base and make preliminary decisions about whether they want to keep selling insurance through the exchanges — and if so, where.
- Congress appears highly likely to repeal the ACA's individual mandate in the meantime. And the Trump administration will also move ahead soon with regulations expanding access to cheap, skimpy short-term health plans.
- Both of those changes will likely pull healthy consumers out of the market for ACA coverage.
- Insurers almost certainly would respond by seeking major premium hikes. The conventional wisdom within the industry and among policy analysts says some parts of the country probably won't have any insurance plans to choose from after this all shakes out.
The bottom line: No outcome from the enrollment period that ends today could make that landscape look much better.
- There's simply no universe in which enrollment will be good enough to make ACA insurers comfortable with the loss of the individual mandate and the return of short-term plans.
- Particularly low enrollment, however, could make this bad landscape look even worse, because insurers would have fewer customers to help absorb the blow from future policy changes.