§ 6699.
(a)
General rule
In addition to the penalty imposed by section 7203 (relating to willful failure to file return, supply information, or pay tax), if any S corporation required to file a return under section 6037 for any taxable year—
(1)
fails to file such return at the time prescribed therefor (determined with regard to any extension of time for filing), or
(2)
files a return which fails to show the information required under section 6037,
such S corporation shall be liable for a penalty determined under subsection (b) for each month (or fraction thereof) during which such failure continues (but not to exceed 12 months), unless it is shown that such failure is due to reasonable cause.
(b)
Amount per month
For purposes of subsection (a), the amount determined under this subsection for any month is the product of—
(2)
the number of persons who were shareholders in the S corporation during any part of the taxable year.
(Added [Pub. L. 110–142, § 9(a)], Dec. 20, 2007, [121 Stat. 1807]; amended [Pub. L. 110–458, title I, § 128(a)], Dec. 23, 2008, [122 Stat. 5116]; [Pub. L. 111–92, § 16(a)], Nov. 6, 2009, [123 Stat. 2996]; [Pub. L. 113–295, div. B, title II, § 208(e)], Dec. 19, 2014, [128 Stat. 4073]; [Pub. L. 115–97, title I, § 11002(d)(1)(OO)], Dec. 22, 2017, [131 Stat. 2061]; [Pub. L. 115–141, div. U, title IV, § 401(a)(299)(E)], Mar. 23, 2018, [132 Stat. 1198].)