If you file for Social Security benefits May 1, 1997, or later, you are assigned one of three new payment days based on the date of birth of the person on whose record your entitlement is established (the insured individual): https://www.ssa.gov/OP_Home%2Fhandbook/handbook.01/handbook-0121.html
My question is why did the SSA do this? What was the reason the birthdate payments after May 1, 1997? Can you post a link on the rationale for doing this? Thank you--
I can't find an official reference that answers your question, but as I recall Social Security's explanation at the time was that paying all benefits on the 3rd of the month created problems for the banking industry. So, spreading payments throughout the month was intended to ease the strain on banking resources. That's just based on my recollection, though, and there's probably more to the story.