N.J. Stat. § 54:10A-5.40
In addition to the franchise tax paid by each taxpayer determined pursuant to section 5 of P.L. 1945, c.162 (C.54:10A-5), for privilege periods ending on or after July 1, 2006 but before July 1, 2010, each taxpayer shall be assessed and shall pay a surtax equal to 4% of the amount of the liability determined pursuant to section 5 of P.L. 1945, c.162 (C.54:10A-5) remaining after application of any credits allowed against that liability other than credits for installment payments, estimated payments made with a request for an extension of time for filing a return, or overpayments from prior privilege periods. The surtax imposed under this section shall be due and payable in accordance with section 15 of P.L. 1945, c.162 (C.54:10A-15), and the surtax shall be administered pursuant to the provisions of P.L. 1945, c.162 (C.54:10A-1 et seq.). Notwithstanding the provisions of any other law to the contrary, no credits shall be allowed against the surtax liability computed under this section except for credits for installment payments, estimated payments made with a request for an extension of time for filing a return, or overpayments from prior privilege periods.
N.J.S. § 54:10A-5.40