The IRS, in Rev. Rul. 2014-14, announced that interest rates will remain the same for the 3rd quarter of 2014. For the 3rd quarter, interest rates are as follows:
1) 3% for overpayments (2% for a corporation);
2) 3% for underpayments;
3) 5% for large corporate underpayments; and
4) 0.5% for corporate overpayments exceeding $10,000.
See also IR-2014-70.