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Tax Planning

Alternative Minimum Tax (AMT) Planning

The Alternative Minimum Tax is a parallel tax system that can significantly increase your tax bill, especially when exercising ISOs, earning large bonuses, or living in high-tax states. Strategic planning can minimize or avoid AMT exposure.

Alternative Minimum Tax (AMT) Planning

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How AMT Works

  • AMT is a parallel tax calculation that disallows certain deductions allowed under the regular tax system
  • You pay the HIGHER of your regular tax or your AMT, it functions as a tax floor
  • TCJA raised AMT exemption amounts and phase-out thresholds, reducing the number of affected taxpayers
  • Key items that trigger AMT: ISO exercises, state and local tax deductions, certain interest deductions

Full Guide

How AMT Works

  • AMT is a parallel tax calculation that disallows certain deductions allowed under the regular tax system
  • You pay the HIGHER of your regular tax or your AMT, it functions as a tax floor
  • TCJA raised AMT exemption amounts and phase-out thresholds, reducing the number of affected taxpayers
  • Key items that trigger AMT: ISO exercises, state and local tax deductions, certain interest deductions

ISOs and AMT

  • Exercising Incentive Stock Options creates an AMT adjustment equal to the spread (FMV minus strike price)
  • This 'phantom income' can generate a massive AMT bill even though you haven't sold the shares or received cash
  • The AMT paid on ISO exercises generates an AMT credit that can be recovered in future years
  • Strategic exercise timing, spreading exercises across multiple years, can keep you below AMT thresholds

AMT Exemption and Phase-Outs

  • The AMT exemption shields a portion of AMTI (AMT taxable income) from the AMT calculation
  • Exemption amounts are indexed for inflation, check IRS.gov for current year amounts
  • The exemption phases out at 25 cents per dollar above the phase-out threshold
  • Once fully phased out, the effective marginal AMT rate can exceed 35% in the phase-out zone

AMT Credit Recovery

  • AMT paid due to 'timing' items (like ISO exercises) generates an AMT credit carryforward
  • The credit is usable in future years when your regular tax exceeds your tentative AMT
  • Selling ISO shares at a gain can help recover prior AMT credits since the regular tax gain is higher
  • Credits can carry forward indefinitely but recovery may take several years depending on income patterns

Planning Strategies

  • Model ISO exercises before executing, calculate the AMT impact at various exercise quantities
  • Spread large ISO exercises across multiple tax years to stay within or just at the AMT exemption
  • Consider exercising ISOs in years with lower regular income to minimize the AMT differential
  • Accelerate income into AMT years (when you're already paying AMT, additional income may be taxed at a lower marginal rate)

Key Takeaways

  • AMT planning is critical for anyone exercising ISOs, the cash tax impact can be enormous
  • Spreading ISO exercises across years is often the most effective AMT mitigation strategy
  • AMT credits from ISO exercises are recoverable but require active planning to reclaim efficiently
  • Work with a tax advisor to model AMT exposure before exercising options or making other AMT-sensitive decisions