(a) No account nor any interest in an account may be assignable or pledged or otherwise used to secure or obtain a loan or other advancement.
(b) No refund of a qualified educational expense payment may be paid by an education institution directly to the designated beneficiary or to the account owner. Any refund of qualified tuition expenses owed by an education institution on account of an overpayment of educational expenses must be refunded to the Plan for credit to the designated beneficiary's account.
(c) A qualified withdrawal that is used to pay for qualified education expenses must be paid jointly to the designated beneficiary and the education institution or directly to the education institution. A payment of qualified education expenses may not be made directly to the beneficiary.
(d) Total contributions to all accounts established on behalf of a particular beneficiary in excess of those reasonably necessary to meet the designated beneficiary's qualified education expenses are prohibited.