Interest rates; underpayments and overpayments. The rates of interest determined under section 6621 of the Code for the calendar quarter beginning July 1, 2008, will be 5 percent for overpayments (4 percent in the case of a corporation), 5 percent for underpayments, and 7 percent for large corporate underpayments. The rate of interest paid on the portion of a corporate overpayment exceeding $10,000 will be 2.5 percent.

Interests in notional principal contracts. This ruling holds that certain interests in notional principal contracts, the returns on which are calculated by reference to an index based on data from a geographically and numerically broad range of United States real estate, are not United States real property interests under section 897(c)(1) of the Code.

This notice invites public comment relating to elections under section 864(f) of the Code to allocate and apportion interest expense on a worldwide affiliated group basis and under section 864(f)(5) to expand a financial institution group of a worldwide affiliated group.

This document contains corrections to Rev. Rul. 2008-17, 2008-12 I.R.B. 626, providing guidance to assist a foreign corporation engaged in the international operation of ships or aircraft, and its shareholders, in determining whether the foreign corporation is organized in a country that grants an “equivalent exemption” from tax for purposes of sections 883(a) and (c) of the Code. The ruling is also intended to assist a nonresident alien individual engaged in the international operation of ships or aircraft in determining whether a country grants an equivalent exemption from tax for purposes of section 872(b). As published, two footnotes were inadvertently omitted from Rev. Rul. 2008-17, Table II (Countries Granting Exemptions from Tax by Income Tax Convention), Column 9 (Cap Gains). Rev. Rul. 2008-17 modified.