N.Y. Comp. Codes R. & Regs. tit. 20, § 4-4.6
(b) For taxable periods commencing on and after January 1, 1978, security and commodity brokers participating in an underwriting syndicate must allocate gross receipts attributable to the primary spread in the following manner:
(c) For taxable periods commencing on and after January 1, 1978, security and commodity brokers participating in an underwriting syndicate must allocate the gross receipts attributable to the selling concession (secondary fees) in the following manner:
Tax Law, § 210(3)(a)(2)