One form of taxation under Subpart F is an “investment in U.S. Property.”  The law treats the investment as a form of taxable repatriation of earnings.  Under certain circumstances, aged accounts receivable may be seen as a form of taxable investment in U.S. property.  Most U.S. tax advisers look to a 60-day rule under which the account receivable is treated as a loan if not settled by the last day of the second month following a sale.  However, that is a safe harbor.  I.R.S. private letter rulings and Tax Court cases have addressed fact patterns in which the account receivable remains open for a much longer time.  Some taxpayers win and others lose.  Elizabeth V. Zanet and Stanley C. Ruchelman explain.