AMT & Pre-tax 401K Deferral

If a client is getting hit with AMT would it make sense to increase their AGI by doing a Roth 401K rather than a traditional 401K since you are losing some of the deductibility of the traditional 401K as well as other deductions.

I know there would be some incremental loss of deductions due to phaseouts but we would be talking an extra $16,500 of taxable income or if husband and wife did Roth 401Ks than it would be an extra $33,000.



The AMT has no effect on the deductibilty of 401k deferrals. The deferrals do not enter into the return at all because they are netted against W-2 income. Even if a self-employed person has 401k contributions shown on the front page of Form 1040, they are not effected either.

Paying more income taxes because earnings are going to a Roth 401k instead of a traditional 401k – makes the Roth 401k an inferior choice.

The AMT is complicated and is very difficult to analyze theoretically – you have to really run the numbers. Paying very high federal income tax lessens your exposure to AMT but if you live in a state with an income tax or are relying on federal gross income to determine your sales tax you are also increasing the add backs for AMT.

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