Why You Might Actually Want To Make After-Tax Contributions To Your 401(k)

The least popular type of contribution you can make to a 401(k) plan is an after-tax contribution that is not a Roth contribution.  It's made with money you’ve already paid tax on (like Roth contributions). The contributions grow tax-free (like a pre-tax and Roth), but all growth will be taxed upon withdrawal. Therefore, the main difference between a Roth and non-deductible contribution is that income and gains from a Roth IRA or 401(k) plan would, upon withdrawal, be tax-exempt, assuming tha...