ADP

Set to 2 different clues across 2 published puzzles, most often “Big inits. in check processing” — The New York Times, Sunday, 1 February 2004.

3 letters

Every clue on record, most used first

Big inits. in check processingonce
The New York Times — Sunday, 1 February 2004
Payroll service giant, initiallyonce
The New York Times — Sunday, 9 November 1997