This excerpt taken from the NKE 10-Q filed Jan 7, 2009.
Purchase of Shares. All amounts withheld from the Compensation of a participant or otherwise contributed by a participant shall be credited to his or her account under the Plan. No interest will be paid on such accounts, unless otherwise determined by the Authorized Officer or required under local law. If amounts are withheld in any currency other than US dollars, the amounts in participants’ accounts shall be converted into US dollars in accordance with procedures approved by the Authorized Officer. On each Purchase Date, the amount of the account of each participant will be applied to the purchase of shares (including fractional shares) by such participant from the Company at the price determined under paragraph 7 above. Any cash balance remaining in a participant’s account after a Purchase Date as a result of the limitations set forth in paragraph 5(b) above shall be repaid to the participant.