securities futures contract
For purposes of this section, the term “securities futures contract” means any security future (as defined in section 3(a)(55)(A) of the Securities Exchange Act of 1934, as in effect on the date of the enactment of this section). The Secretary may prescribe regulations regarding the status of contracts the values of which are determined directly or indirectly by reference to any index which becomes (or ceases to be) a narrow-based security index (as defined for purposes of section 1256(g)(6) ).