On March 26, 2015, the House of Representatives passed H.R. 2, the Medicare Access and CHIP Reauthorization Act of 2015, which would replace the Sustainable Growth Rate (SGR) formula, among other changes; the bill is currently pending in the U.S. Senate. H.R. 2 includes a provision that would prohibit Medicare supplemental insurance (Medigap) policies from covering the Part B deductible for people who become eligible for Medicare on or after January 1, 2020. This data note looks at the number and share of “new” Medicare beneficiaries who would be affected by the Medigap provision in H.R. 2, if it had been implemented in 2010, using the most current data sources available, and examines trends in Medigap enrollment among new beneficiaries since 2000.