1099-MISC information returns would be required if anyone managed to collect $600 or more in the sweepstakes and any other give-aways from the bank. Based on your question, it would not be expected that you'd be issuing any 1099-MISC returns for the sweepstakes winners.
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John S. Burnett
BankersOnline.com
Fighting for Compliance since 1976
Bankers' Threads User #8