28 U.S.C. § 1658 : US Code - Section 1658: Time limitations on the commencement of civil actions arising under Acts of Congress

      (a) Except as otherwise provided by law, a civil action arising
    under an Act of Congress enacted after the date of the enactment of
    this section may not be commenced later than 4 years after the
    cause of action accrues.
      (b) Notwithstanding subsection (a), a private right of action
    that involves a claim of fraud, deceit, manipulation, or
    contrivance in contravention of a regulatory requirement concerning
    the securities laws, as defined in section 3(a)(47) of the
    Securities Exchange Act of 1934 (15 U.S.C. 78c(a)(47)), may be
    brought not later than the earlier of - 
        (1) 2 years after the discovery of the facts constituting the
      violation; or
        (2) 5 years after such violation.