383655dd_s_Relating_to_Security_Futures__Description_of_Offset
[0] 4 Individual stock or narrow-based security index [Initial Margin Requirement] The initial margin required under Regulation T for the short stock or stocks. 5% of the current market value as defined in Regulation T of the stock or stocks underlying the security future. [Description of Offset] 
Long security future and short position in the same security (or securities basket) underlying the security future
Final Rule: Customer Margin Rules Relating to Security Futures