A proposal by the Centers for Medicare and Medicaid Services to publicly release pricing data that is used when insurers make bids on Medicare Advantage plans has garnered fierce opposition from — you guessed it — insurance companies.

As is the case for the Affordable Care Act individual insurance market, insurers that seek to offer Medicare Advantage plans must annually submit bids outlining the premiums they will charge. They are required to justify the premiums by submitting their projected medical loss ratio, or the amount of premium revenue that will be directed towards medical care, rather than profit.

“(W)e have the authority to use such information for purposes of improving public health through research on the utilization, safety, effectiveness, quality and efficiency of health care services,” explained the agency in a brief announcing the proposed rule change in July.

“Release of (medical loss ratio) data from the (Medicare Advantage) and Part D programs could lead to research into how managed care in the Medicare population differs from and is similar to managed care in other populations (such as the individual and group markets) where (medical loss ratio) data is also released publicly; such research could inform future administration of these programs,” it later added.

Cigna, Humana, Anthem, and the Blue Cross Blue Shield Association have raised objections to the proposed rule.

One of the concerns they raise is that providers might use the information as leverage during negotiations with insurers over pricing.

Similarly, they argue that making the data on pricing public will allow providers to raise their prices overall. When hospitals are not sure of how much their competitors are charging, argue the insurers, they will generally offer lower prices.

Consumer advocates, however, are not inclined to side with the insurance industry on this one.

“This effort by (the Centers for Medicare and Medicaid Services) is consistent with a lot of other efforts at the state and federal level to provide more upstream transparency about provider and carrier rates, the ultimate goal of which is to reduce high outlier prices and squeeze out excess margin,” Katherine Hempstead, a senior adviser at the Robert Wood Johnson Foundation, told Modern Healthcare.

Audits of Medicare Advantage plans from 2007 — only recently made public — reveal many of the plans were accused of “persistently” overbilling the federal government for a variety of medical services.