What is the plural of W-9?

Answer by  technogeek (6640)

The grammatically correct plural of W-9 would be W-9's because there is no actual word connected to the phrase, contrary to RBI (Runs Batted In) in baseball. A batter would have one RBI and two R's-BI, because the plural would be on Runs not on In.

Answer by  bigdog22 (308)

The correct plural form of the document W-9 is W-9s. A better rendition would be to write out W-9 "forms. " I have seen this before.