An outpatient prescription drug benefit available to Medicare beneficiaries. For those who enroll, this benefit helps pay for drug costs, with catastrophic coverage for very high drug costs, and additional financial assistance through the Low-Income Subsidy (LIS) program for beneficiaries with low incomes and modest assets. Funding for Part D comes from general federal government revenue (76 percent), beneficiary premiums (14 percent), and contributions from the states for people who qualify for both Medicare and Medicaid (10 percent).