The Protected Filing Date (PFD) is the date you contacted Social Security and asked to file an application.
What is so special about that?
The PFD is used to determine how far back your benefits can be paid.
What makes it “protected?”
Since the application process takes time, Social Security does not want to penalize you for delay between the time you ask to start an application and the time you actually finish it.
For example: if you contact Social Security on January 2nd to start an application (Social Security is closed on new year’s day), but do not turn in all the paperwork until February 1st, Social Security will use January 2nd as your protected filing date, even though you did not actually turn in your application until February.
This could mean an extra month of benefits for you.