Reminder: April 16, 2018 is the last day to make a contribution to a Traditional IRA or Roth IRA for the 2017 Tax Year. The United States Letter Carriers Mutual Benefit Association (MBA) has announced that the Interest Rates paid on MBA Policies will remain the same for 2018. The MBA is currently paying 3.25% interest on the Retirement Savings Plans (except for those policies which guarantee a higher minimum rate).