A rule created by the 2010 healthcare law and finalized Friday will yield about $1.3 billion in insurance rebates for nearly 16 million Americans, according to estimates by the Kaiser Family Foundation.

The rule, known as the medical loss ratio (MLR), mandates that insurers spend roughly 80 percent of all premiums on healthcare rather than on marketing, executive bonuses or other administrative costs.

The rebates — which the Obama campaign reportedly sees as a “stealth weapon” for improving opinion of the health law — will arrive no later than August 1.

“If the insurance company fails to meet this standard … in any year, they have to pay you a rebate,” Kathleen Sebelius, Secretary of the Health and Human Services (HHS) Department, wrote in a blog post.