Amends 12 U.S.C. 1761b to modify the board meeting requirements by adding a new subsection specifying different minimum meeting frequencies for de novo credit unions, low-risk credit unions, and higher-risk credit unions.

Adds a new paragraph (l) (Individual retirement plans) to 26 U.S.C. 6501 defining, for purposes of any tax imposed by sections 4973 or 4974 in connection with an individual retirement plan, which 'return' is used to determine the limitations period and providing rules for individuals not required to file; see bill text adding new paragraph to section 6501.

Amends Part 5 of title I of ERISA by adding a new section establishing a 'Retirement Savings Lost and Found' (an online searchable database managed by the Department of Labor) with information-collection requirements for plan administrators and related privacy, access, and audit provisions.

Makes conforming amendments to the table of contents for the Employee Retirement Income Security Act of 1974 by inserting new items related to newly added sections (e.g., the Retirement Savings Lost and Found).

Amends section 72(t)(2)(H)(v)(I) to limit the period in which a taxpayer may repay a qualified birth or adoption distribution to a 3‑year period beginning the day after the distribution was received (changes wording from 'may make' to a specified 3‑year repayment window).

Amends 26 U.S.C. 1042(c)(1)(A) by striking "domestic C corporation" and inserting "domestic corporation"; also adds a new subsection (h) limiting the election for S corporation stock to not more than 10 percent of the amount realized on such sale.

Adds a new subsection (c) to 29 U.S.C. 1052 (section 202 of ERISA) establishing a special rule for certain part‑time employees regarding the period of service required as a condition of participation (including treatment of two consecutive 12‑month periods with at least 500 hours of service and related coordination and exception rules).

Amends 29 U.S.C. 1053 (section 203(b) of ERISA) by redesignating paragraph (4) as paragraph (5) and inserting a new paragraph (4) that treats certain 12‑month periods with at least 500 hours of service as years of service for part‑time employees (with a specified substitution in a subparagraph).

Amends 29 U.S.C. 1056 (section 206 of ERISA) by adding a new subsection (h) containing special rules applicable to inadvertent benefit overpayments (including rules on when a fiduciary is not treated as failing to comply for electing not to seek recovery, conditions on recoupment from participants, employer funding obligations, and protections where participants are not culpable).

Amends subsection (b) of 29 U.S.C. 1108 (section 408(b) of ERISA) by adding a new paragraph (21) to permit the provision of a de minimis financial incentive described in section 401(k)(4)(A) of the Internal Revenue Code (cross‑referencing 403(b)(12)(A)).