As of April 17, Medicare is using a new interest rate for under- or overpayments. Following a Department of Treasury notice, the Department of Health and Human Services is now using a 10.375 percent rate, according to recent transmittal 313. That’s down slightly from the 10.75 percent rate for the previous quarter, the Centers for Medicare & Medicaid Services notes in the transmittal at www.cms.gov/Regulations-and-Guidance/Guidance/Transmittals/2019Downloads/R313FM.pdf.