2. Money for advertising to let people know that it’s time to sign up has been decreased by 90 percent. That advertising often aimed for people on the fence about enrolling who were younger and healthier — the most desirable customers.
3. Money for navigators who guide people through the sign-up process and help them understand their best options has also been cut deeply, by different amounts depending on the organization. Navigators are still out there, but there are fewer of them.
4. The federal government will stop paying "cost-sharing reduction" subsidies to insurance companies, subsidies that helped lower costs for lower-income customers on the exchange. The companies still must offer lower cost policies to those people, however, so in the end they will charge other people more in order to make up the difference. Some insurers have also cut back their coverage areas as a result.
5. The sign-up website, healthcare.gov, will go down for maintenance most Sunday mornings during open enrollment and also early in the morning of the first day, Wednesday. It remains to be seen how much of a change this is from the Obama administration, which also shut it down for maintenance during some Sunday mornings. The Trump administration says it merely left itself a window of midnight to noon for maintenance work, and it could be down far less than that.
6. When insurers get money from a customer who is signing up, they are now allowed to apply the money first to unpaid debt from the past year of premiums before they apply it to the new year’s policy and make the person insured. Previously, there was a three-month grace period.
7. The ACA had created “special enrollment periods” — periods outside the fall open enrollment window when particular groups of people can enroll off the clock. That includes people having a life event such as losing employer health insurance, moving to a new area or getting divorced. When people apply for this, they will now universally be required to show proof that they are eligible first. The Obama administration had started a pilot pre-verification program, but it applied only to half of the applicants.
8. Changes have also been made under the ACA to insurance that is not sold on the exchange market. For example, employers who offer insurance to their employees will now have much more flexibility in whether to offer coverage for contraception.
9. Some of those changes could still have a big ripple effect on the Obamacare exchange plans. For one, President Donald Trump signed an order to expand access to "association plans" that allow small companies to band together to buy health insurance. This will take some time to go into effect as the federal government sets it up. But in full swing, it is meant to offer cheaper plans that cover less.
10. One other change that hasn’t been fully fleshed out yet, but has the potential to be major, was signed by Trump the same day. The administration may allow access to “short-term plans” all year long that are exempt from many of the robust coverage requirements of Obamacare. If the change rolls out that way, it could suck big numbers of healthy (cheap) customers out of the exchanges. Again, such plans are not available as an alternative for 2018 at this time.