Are 150-year-old Americans receiving Social Security checks, as Elon Musk said?

 https://www.politifact.com/article/2025/feb/17/are-150-year-old-americans-receiving-social-securi/

Why 150-year-old figures may exist in the Social Security database

Social media commenters came up with one possible explanation for the 150-year age, and experts who have worked closely with the Social Security Administration told PolitiFact it was plausible. 

Under an international standard called ISO 8601, a missing value for a date is coded as May 20, 1875, because that was the date of an international standards-setting conference held in Paris, known as the "Convention du Mètre."

For that reason, under some coding systems, a missing value for a date will default to 1875 — which in the year 2025 produces a round figure of 150.