A provision in the Affordable Care Act, the healthcare reform act commonly referred to as Obamacare, will require health insurance companies to return $500 million in rebates this summer back to consumers.

Insurers expected to pay the rebates did not adhere to the Medical Loss Ratio (MLR) or "80/20" rule, which stipulates that insurance companies should spend at least 80 percent of premiums on patient care and quality improvement, instead of overhead costs or executive bonuses.

About 8.5 million enrollees will receive rebates, either by check, direct payment to a credit or debit card account, a reduction in future premiums, or indirectly through their employers. The rebate will be accompanied by a letter to customers explaining how their premiums were spent.

"The health care law is providing consumers value for their premium dollars and ensuring the money they pay every month to insurance companies goes toward patient care," said Department of Health and Human Services Secretary Kathleen Sebelius. "Thanks to the law, 8.5 million Americans will receive $500 million back in their pockets and purses."

The $500 million in rebates is roughly half of what insurance companies were required to return to consumers last year, which may mean that insurers are following the rule more closely.

Lower spending on premiums occurred last year because of the MLR rule and another rule that requires a review of any increase in premiums over 10 percent, according to Gary Cohen, deputy administrator at the Centers for Medicare and Medicaid Services. The rules motivated health insurance companies to be more efficient in their operations, he said.

Cohen admits that other market forces could be driving the decrease in health insurance premiums, such as the overall slowdown of healthcare spending partly attributed to the recession.

Overall, these changes are estimated to have saved $3.4 billion for 77.8 million health insurance consumers last year. In a press release, the Department of Health and Human Services claims that the Affordable Care Act is responsible for $5 billion in premium-related savings since these parts of the act were enacted in 2011.

Signed into law in 2010, the Patient Protection and Affordable Care Act's many components have been gradually enacted since its inception. One of the hallmark programs, state-run health insurance exchanges, will be available to customers in October to purchase health insurance plans that will be effective in January 2014.