Regulation DD is essentially a disclosure regulation, and doesn't speak to your ability to offer this promotion. You may be thinking about Regulation Q, which limits deposit premiums, but only on demand deposit accounts. You're on safe ground on both regulations here.
I do think that these payments fit the definition of "bonus" under Regulation DD, however, to the extent that they are very likely to exceed $10 per year per account. Accordingly, if you advertise this program (why bother with it if you don't advertise?) you will need to comply with the Reg. DD advertising rules in section 230.8.
I will let someone else speak to the question of IRS rules on whether these payments are considered interest.
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John S. Burnett
BankersOnline.com
Fighting for Compliance since 1976
Bankers' Threads User #8