26 U.S. Code § 6248 - Period of limitations for making adjustments
In the case of a false or fraudulent partnership return with intent to evade tax, the adjustment may be made at any time.
If any partnership omits from gross income an amount properly includible therein which is in excess of 25 percent of the amount of gross income stated in its return, subsection (a) shall be applied by substituting “6 years” for “3 years”.
In the case of a failure by a partnership to file a return for any taxable year, the adjustment may be made at any time.
Pub. L. 114–74, title XI, § 1101(b)(2), (g), Nov. 2, 2015, 129 Stat. 625, 638, provided that, applicable to returns filed for partnership taxable years beginning after Dec. 31, 2017, with certain exceptions, this section is repealed.