One way to improve the risk pool on the Affordable Care Act’s health insurance marketplaces is to get more young adults to purchase coverage on the exchanges, so HHS has laid out some of its strategies to court younger people who haven’t enrolled in prior years.

The plans build on recently proposed rules to strengthen the ACA risk pool, like imposing a three-month limit on short-term insurance plans which don’t meet minimum coverage standards.

The first step would be to court potential customers who paid the tax penalty for being uncovered, or claimed an exemption from the fee. HHS said people under the age of 35 made up 45 percent of those paid a penalty or claimed an exemption from the penalty in 2014.

How and when those young adults are contacted is also part of the strategy. HHS said the last open enrollment period found younger people were twice as likely to enroll because they were e-mailed about marketplace coverage. So for the next enrollment period, HHS will contact customers “in near-to-real time” when they open an application but don’t complete it or select a plan but don’t pay their first premium.

Other strategies including sending more detailed information to young adults who are aging out of existing coverage, such as 19-year-olds who can’t be covered by Medicaid or CHIP, or 26-year-olds who had been included on their parents’ health plans.

The next open enrollment period runs from Nov. 1, 2016 to Jan. 31, 2017.