Summary: Pursuant to a congressional request, GAO reviewed whether the Medicare and Medicaid Coverage Data Bank will enable the Health Care Financing Administration (HCFA) to more effectively administer the Medicare Secondary Payer (MSP) program. GAO noted that: (1) the data bank may not be able to realize the anticipated level of savings and faces immediate implementation barriers; (2) the data bank would duplicate existing legislatively mandated MSP efforts; (3) the data bank would be an inefficient and costly method to identify potential MSP cases, since 98 percent of the data collected would not be relevant to the MSP program; (4) the relevant information in the data bank would be incomplete for MSP purposes; (5) HCFA will need about $17 million to design and implement the data bank and an additional $25 million to $30 million annually to administer the data bank; and (6) employers may not be able to comply with Office of Management and Budget reporting requirements because HCFA has not issued implementation guidance on how employers should report information to the data bank.