Today the IRS published the following Chief Counsel Advice relating to international taxation:
CCA 201205007: Credit card interest income earned by U.S. citizens and resident alien customers living outside the U.S. was foreign source income. The CCA relied upon the substantial presence test to determine U.S. or foreign residency. In addition, ATM fees earned related to ATM transactions located outside the U.S. were considered income from services that were performed in the U.S. and were therefore U.S. source income.
[I am not sure that I agree with the conclusion related to the ATM fees.]