37 CFR §1.481

1. (a)The handling and preliminary examination fees shall be paid within the time period set in PCT Rule 57.3. The handling fee or preliminary examination fee payable is the handling fee or preliminary examination fee in effect on the date of payment.
   1. (1)If the handling and preliminary examination fees are not paid within the time period set in PCT Rule 57.3, applicant will be notified and given one month within which to pay the deficient fees plus a late payment fee equal to the greater of:
      1. (i)Fifty percent of the amount of the deficient fees, but not exceeding an amount equal to double the handling fee; or
      2. (ii)An amount equal to the handling fee (PCT Rule 58bis.2).
   2. (2)The one-month time limit set in this paragraph to pay deficient fees may not be extended.
2. (b)If the payment needed to cover the handling and preliminary examination fees, pursuant to paragraph (a) of this section, is not timely made in accordance with PCT Rule 58bis.1(d), the United States International Preliminary Examination Authority will declare the Demand to be considered as if it had not been submitted.