What is a CP2100 or CP2100A Notice?
A… It is a notice that tells a payer that he or she may be responsible for backup withholding. It is accompanied by a listing of missing, incorrect, and/or not currently issued payee TINs. Large volume filers will receive a CD or DVD data file CP2100, mid-size filers receive a paper CP2100, and small filers receive a paper CP2100A.