(a) Date of assessment with respect to state change.
1. Taxpayer self-assessment. The tax is deemed to be assessed with regard to a report of state change under 830 CMR 62C.30A.1(3) at the time when the report of state change is duly filed.
2. Commissioner deficiency assessment. For the purposes of 830 CMR 62C.30A.1, the tax is assessed upon the issuance of a Notice of Assessment to a taxpayer, or the entry in the Commissioner’s assessment records of an amount due from the taxpayer, if such entry predates the Notice of Assessment.
(b) Determination of assessment amount with respect to state change.
1. Taxpayer self-assessment. Taxes are deemed to be assessed with the taxpayer's calculation and declaration of the tax due, as provided under M.G.L. c. 62C, § 26 (a), reported as prescribed by the Commissioner by the taxpayer or the taxpayer's representative and duly filed with the Commissioner. The deemed assessment is the amount due before any offsets are claimed by the taxpayer.
2. Deficiency assessment by the Commissioner.
a. Full amount of tax not assessed. If the Commissioner determines from the taxpayer's report of state change or upon investigation that, as a result of the change in tax liability to another jurisdiction and consequent change in the Massachusetts tax credit claimed by the taxpayer, the full amount of tax has not been assessed or deemed to be assessed, the Commissioner will assess, notwithstanding the three year limitation in M.G.L. c. 62C, § 26, the full amount of tax with interest, as provided in M.G.L. c. 62C, § 32, from the due date of the original return. Any assessment under 830CMR 62C.30A.1(4)(b) 2. will be made in the manner provided in 830 CMR 62C.26.1.
b. Limitation period for assessment. The Commissioner will make any deficiency assessment within one year of receiving a taxpayer's report of state change, as provided in 830 CMR 62C.30A.1(3). If no report of state change is filed as provided in 830 CMR 62C.30A.1(3), the Commissioner will make any deficiency assessment within two years of receiving information from the other jurisdiction that it has made a final determination of a taxpayer's tax liability that is less than originally reported.
c. Limitation on items assessed. Any assessment made under 830 CMR 62C.30A.1(4)(b)2. is limited to changes in a taxpayer's tax liability directly attributable to changes, adjustments, or corrections to the taxpayer’s tax owed to another jurisdiction resulting in a final determination.