20 C.F.R. § 416.732
(a) We will find that you have good cause for failure to report timely and we will not impose a penalty deduction, if—
(2) Your failure or delay in reporting is not willful. “Not willful” means that—
(ii) You did not intentionally, knowingly, and purposely fail to make a required report.
However, in either case we may require that you refund an overpayment caused by your failure to report. See subpart E of this part for waiver of recovery of overpayments.
[59 FR 1636, Jan. 12, 1994]