This excerpt taken from the NKE 10-K filed Jul 28, 2006.
Reserve for Uncollectible Accounts Receivable
We make ongoing estimates relating to the collectibility of our accounts receivable and maintain a reserve for estimated losses resulting from the inability of our customers to make required payments. In determining the amount of the reserve, we consider our historical level of credit losses and make judgments about the creditworthiness of significant customers based on ongoing credit evaluations. Since we cannot predict future changes in the financial stability of our customers, actual future losses from uncollectible accounts may differ from our estimates. If the financial condition of our customers were to deteriorate, resulting in their inability to make payments, a larger reserve might be required. In the event we determined that a smaller or larger reserve was appropriate, we would record a credit or a charge to selling and administrative expense in the period in which we made such a determination.