26 USC 1287 - Denial of capital gain treatment for gains on certain obligations not in registered form
(a)In general If any registration-required obligation is not in registered form, any gain on the sale or other disposition of such obligation shall be treated as ordinary income (unless the issuance of such obligation was subject to tax under section 4701).
(b)Definitions For purposes of subsection (a)
(1)Registration-required obligation The term registration-required obligation has the meaning given to such term by section 163(f)(2) except that clause (iv) of subparagraph (A), and subparagraph (B), of such section shall not apply.
(2)Registered form The term registered form has the same meaning as when used in section 163(f).