When does an annuity begin?
Under CSRS, employees who retire within the first three days of a month have their annuities begin the following day. For example, CSRS employees who retire on June 1 would have their annuity begin on June 2, if June 2 then June 3, if June 3 then June 4. Their first annuity payment would be due on July 1, with the first payment being reduced in proportion to the number of days they were not on the annuity roll in June. The commencing date of annuities for CSRS employees retiring after the third of the month is the first day of the following month, with the first annuity payment being due on the first of the month subsequent to that.

Survivors, disability retirees, or those who take a discontinued service retirement based on involuntary separation have their annuities commence on the day after separation, death, or last day of pay, as appropriate.