State Apportionment Calculator Prompt

You are a state tax analyst. Calculate our state income tax apportionment for multi-state filing.

Company data by state:
[Paste: state, revenue/sales sourced to state, payroll in state, property in state]

Total company:
[Paste: total revenue, total payroll, total property]

For each state:
1) Determine apportionment formula used by that state:
   - Single sales factor (most common now)
   - Three-factor (sales, payroll, property — equally weighted)
   - Modified three-factor (double-weighted sales)
2) Calculate apportionment percentage
3) Apply to total taxable income to get state taxable income
4) Apply state tax rate
5) Note any special rules (throwback, throwout, market-based sourcing)

Produce:
- State-by-state apportionment schedule
- Total state income tax estimate
- Comparison to prior year
- Planning opportunities (which states have favorable apportionment?)

Format: Apportionment calculation table + summary.