The Centers for Medicare & Medicaid Services (CMS) Administrator Marilyn Tavenner plans to resign, effective at the end of February, Health and Human Services (HHS) Secretary Sylvia Mathews Burwell wrote in an email this morning . Andrew Slavitt, principal deputy administrator, will take on the role of acting administrator.

"It goes without saying that Marilyn will be remembered for her leadership in opening the Health Insurance Marketplace. In so doing, she worked day and night so that millions of Americans could finally obtain the security and peace of mind of quality health insurance at a price they could afford. It's a measure of her tenacity and dedication that after the tough initial rollout of Healthcare.gov, she helped right the ship, bringing aboard a systems integrator and overseeing an overhaul of the website," Mathews wrote in the email.

Mathews noted that Tavenner is a big reason as to why roughly 10 milllion Americans gained health coverage since last year--which, as Mathews also pointed out, was the largest increase in four years.

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