Public Law 110-185, § 101 authorizes the Internal Revenue Service (IRS) to issue economic stimulus payments to eligible taxpayers. The payments are the result of a federal credit treated as a payment against federal income tax. The IRS will start issuing the payments beginning in April of 2008.
The amount of the credit is not included in the taxpayer's federal gross income.  Massachusetts gross income is federal gross income with certain modifications not relevant here. G.L. c. 62, § 2(a). Since the economic stimulus payments are not included in federal gross income, they are not included in Massachusetts gross income and thus not subject to the Massachusetts personal income tax.
/s/Navjeet K. Bal
Navjeet K. Bal
Commissioner of Revenue
May 1, 2008
 Staff of the Joint Comm. on Taxation, 110 th Cong., Technical Explanation of the Revenue Provisions of the H.R. 5140, The "Economic Stimulus Act of 2008."