Many states base their tax on a percent of the Federal income tax, or at least begin with Federal taxable income. Massachusetts requires a completely separate calculation based on complex rules that in many ways differ from federal tax rules.
Many factors contribute to the complexity of Massachusetts taxes.
For almost ten years, Massachusetts taxpayers have been using the IRC that was in place on January 1, 1988. The recently enacted deficiency budget legislation included a provision updating the Massachusetts Personal Income Tax Law to recognize the IRC as amended to January 1, 1998. This change will greatly reduce the complexity and record keeping for individuals, partnerships and S-corporations. This is a major step toward simplification for Massachusetts taxpayers. Still, Massachusetts tax law remains very complex.