Interest rates are determined each June 1 for the upcoming award year by adding a defined percentage to the high yield of the 10-year Treasury note auctioned at the final auction prior to June 1. As a result of the auction on May 8, 2019, the interest rate for federal Direct Loans first disbursed on or after July 1, 2019 will decrease from 5.045% to 4.529% for undergraduate Direct Loans, from 6.595% to 6.079% for graduate/professional Direct Unsubsidized Loans, and from 7.595% to 7.079% for Parent and Grad PLUS loans. The interest rate caps for these loans are 8.25 percent, 9.5 percent, and 10.5 percent, respectively.
https://www.treasurydirect.gov/instit/annceresult/press/preanre/2019/R_20190508_1.pdf