The Case Against Roth 401(k)
To Roth or not to Roth, that is the question. Starting in 2008, like many other employers, my employer also started offering the Roth 401k option in our 401(k) plan. This question of whether one is better off with contributing to the Traditional 401k or contributing to the Roth 401k has been the subject of a lot of debate. Although there is no one-size-fits-all answer, I think for most people the majority, if not 100%, of the contribution should go to a Traditional 401(k). I will state my case against the Roth 401(k) in this post.
The basic premise of a Roth 401(k), and to some extent a Roth IRA, is that of prepayment. You are prepaying the tax now so you don't have to pay tax later. This prepayment concept is not uncommon. For example, buying a season ticket is prepaying for the individual events. Buying a timeshare is prepaying for vacation accommodation. Whenever we deal with a prepayment scheme, we have to assess whether prepaying is "worth it." The same paradigm also applies to Traditional versus Roth 401(k). There are several factors that make prepaying the taxes now not worth it.
1. Fill in lower tax brackets in retirement. I showed in a previous post Commutative Law of Multiplication that if the marginal tax rate at retirement is the same as it is now, the Traditional and Roth 401(k)'s are equivalent. If the marginal tax rate is higher now than in retirement, one is better off contributing to a Traditional 401k. If the current marginal tax rate is lower, one is better off contributing to a Roth 401k. But that applies only to the marginal dollar, which is the last dollar you can shift between Traditional and Roth 401(k). It is not necessarily the case for the entire contribution or the average dollar. The tax system in the United States is progressive and it will probably stay that way. That means that income is taxed at increasing rates as it goes higher. Even if you think the marginal tax rate in the future will be higher, there will still be lower brackets and these lower brackets should be filled with money from a Traditional 401(k).





