11 C.F.R. § 400.53 Disposal of excess contributions.
Title 11 - Federal Elections
(a) The candidate's authorized committee must refund the excess contributions to individuals who made contributions to the candidate or the candidate's authorized committee under this part. The refund to each individual must not exceed that individual's aggregate contributions to the candidate or the candidate's authorized committee for the relevant election cycle. (b) The amount of any refund checks, made under paragraph (a) of this section that are not cashed, deposited, or otherwise negotiated within 6 months of the date of the refund check must be disgorged to the United States Treasury. The candidate's authorized committee must disgorge this amount to the United States Treasury within nine months of the election.
Title 11: Federal Elections
PART 400—INCREASED LIMITS FOR CANDIDATES OPPOSING SELF-FINANCED CANDIDATES
Subpart E—Disposal of Excess Contributions
§ 400.53 Disposal of excess contributions.