INTEREST ON UNDERPAYMENTS
- Section 301.6601-1 - Interest on underpayments
- Section 301.6602-1 - Interest on erroneous refund recoverable by suit
- Section 301.6611-1 - Interest on overpayments
- Section 301.6621-1 - Interest rate
- Section 301.6621-2T - Questions and answers relating to the increased rate of interest on substantial underpayments attributable to certain tax motivated transactions (temporary)
- Section 301.6621-3 - Higher interest rate payable on large corporate underpayments
- Section 301.6622-1 - Interest compounded daily