The Obama administration on Monday announced new regulations intended to strengthen the health of the ObamaCare marketplaces and improve the experience for insurers.

The range of technical tweaks announced by the Centers for Medicare and Medicaid Services (CMS) on Monday is the latest step in a range of actions the administration has taken this year to address some complaints by insurers. 

Recent exits from the healthcare reform law’s marketplaces by big insurers like Aetna and UnitedHealthcare, citing financial losses due to problems with the ObamaCare system, have raised questions about the sustainability of ObamaCare. 

“As the Marketplace continues to grow and mature, one of our most important priorities is to study data, listen to a range of market participants, test out different approaches, and adapt to what we see and hear,” Kevin Counihan, the administration’s ObamaCare CEO, said in a statement. “We have a number of tools to make adjustments like the ones we are proposing today, and are confident in our ability to make the Marketplace an even more attractive market for consumers and health plans alike.”

The rule proposed on Monday would make some changes that have been sought by insurers to an ObamaCare program called risk adjustment, which redistributes money from insurers with healthier enrollees to those with sicker, costlier ones. 

The rule proposes to make the formula more accurate by using prescription drug data as a source of information about enrollees’ health. 

The proposal also includes new protections for insurers with extremely high-cost enrollees. Costs above $2 million for any one individual would be shared among insurers. 

The CMS is also looking for comments on additional ways to tighten up the rules around extra sign-up periods that insurers have complained are driving up their costs when people game the system. The administration earlier this year for the first time announced that it would start making enrollees provide documentation to prove that they actually qualified for the extra sign-up periods, for example proving that they just moved residences. 

The administration is also looking to loosen the rules to give insurers more flexibility in how they design their plans, particularly in the requirements for the least generous “bronze” plan. 

Still, some of the major changes sought by insurers, like repealing the Health Insurance Tax or allowing for charging older people higher premiums, would require action from Congress, which remains mired in political fighting over the law.