We’re all told that we should use IRA and 401k accounts to save for retirement due to their great tax benefits. But how valuable exactly are those benefits? ? A huge difference? A little difference? This Morningstar article crunches some numbers for “traditional” pre-tax IRA/401ks within a broadly-representative tax situation and three example portfolios. (Although the benefits should be basically the same for Roth accounts, as they end up assuming the same tax rate during the working and retirement years.)
A one-time $5,000 contribution (pre-tax) is invested for 40 years within both the tax-deferred IRA/401k and a taxable brokerage account. The three example portfolios are “100% zero-dividend stocks”, “100% stock index”, and “60% stocks/40% bonds balanced” – essentially most to least tax-efficient. All are assumed to return 8% annually. Here are the results:
Here is the conclusion, quoted directly from the article:
To address this article’s original question, for investments made over a full working career, from age 25 to 65, IRA/401(k) accounts improve the final aftertax value of the study’s assets by 17% for a no-dividend portfolio, 30% for a stock market index fund, and 44% for a low-turnover balanced fund. Those figures, of course, will vary according to personal circumstances, but I conducted enough offscreen spreadsheet tests, using different tax brackets, to conclude that they are broadly representative.
As you might expect, the advantage is greater when the portfolio is less tax-efficient. Anything that spins off dividends, capital gains, and interest should go in the tax-deferred vehicle.
If you assume the use of the most popular target date retirement funds, they are 90% to 100% stock market index for the majority of the working years (25-65). So there you have it. A 30% boost is a reasonable estimate for most people to carry around in their heads. Roughly 1/3rd more. That’s a lot!
In short, IRA/401(k) plans are a very good deal. And should the latter offer a company match, they become a truly great deal.
