There are two conditions for a fee payment to be valid:
(i)it must relate to pending proceedings; and
(ii)it must be made in due time, i.e. the date of payment (see A‑X, 4) must be on or after the due date (see A‑X, 5.1.1). In addition, for a time limit for payment to be deemed to have been observed, the full amount of the fee must have been paid in due time.
An essential condition for a valid payment to the EPO in the case of payment or transfer to the bank account held by the European Patent Organisation is that the amount is entered in that account. The payment is valid in respect of the amount entered. If an insufficient amount has been paid by mistake, it is not possible to rectify the error by having the shortfall paid subsequently deemed to be paid on the original date of payment. The same applies to payments made via credit card. Payment is a matter of fact whereby a certain amount is transferred to and put at the disposal of the EPO. It is not, therefore, a document filed with the EPO or a procedural declaration which may be corrected pursuant to Rule 139. However, the EPO may, where it is considered justified, overlook any small amounts lacking without prejudice to the rights of the person making the payment (Art. 8 RFees).
In the case of payment via deposit account the essential condition, in addition to those specified under points (i)-(ii) above, is that the debit order clearly specifies the purpose of payment by indicating the fee intended to be paid, thus authorising the EPO to debit the fee for this particular purpose. Furthermore, the EPO can only debit the full amount of the fee if there are sufficient funds in the deposit account. In respect of underpayments due to incorrect information given in a debit order, see A‑X, 4.2.3. See also A‑X, 7.1.2 concerning corrections of the purpose of payment.