Taxes on Production & Imports less Subsidies (TOPI) is one of the four components of Value Added. It includes sales and excise taxes, customs duties, property taxes, motor vehicle licenses, severance taxes, other taxes, and special assessments.
Because TOPI is net of subsidies, it can be negative for a given Industry in a given year if that industry received more subsidies from the government than it paid out in these specific taxes in that year.
I-O models by default treat TOPI as a leakage, meaning that any TOPI generated as part of an analysis will not generate any additional effects.
Note: TOPI does not include all taxes paid by an industry. For example, social insurance taxes are a part of Employee Compensation, and profits taxes are part of Other Property Income.