"These final regulations do not provide substantive rules on index options. Rather, to determine whether an index substantially all the components of which are specified securities is a broad-based index under section 1256(g)(6)(B), a broker must look to rules established by the Securities Exchange Commission and the Commodities Futures Trading Commission that determine which regulator has jurisdiction over an option on the index." https://www.irs.gov/irb/2013-20_IRB/ar07.html
