FREE NEWSLETTER
I have a question for my fellow humble members of this Forum.
I’ve often heard financial professionals discourage borrowing from a 401(k) plan, citing what they call a “double taxation” issue. The claim goes like this: when you repay your 401(k) loan, you use after-tax money, and then later, when you withdraw funds from your 401(k) in retirement, you’ll pay taxes again on that same money. Therefore, they say, you’re taxed twice.
While there are many valid pros and cons to taking a 401(k) loan, this particular “double tax” argument never quite sat right with me. For one, if you borrow from your 401(k) and instead of spending the money, use it to repay pay-off the loan quickly—before any meaningful interest accrues—there’s no additional tax involved.
Still, I recently heard the same claim again in a podcast, repeated confidently by another financial professional. That made me revisit my thinking—and I continue to believe this reasoning is flawed.
Here’s why: when you borrow from your pre-tax 401(k), the loan amount you receive is tax-free. You can spend it just like after-tax money, but without paying any tax upfront. If you had instead used money from your regular income or savings, that money would already have been taxed before you could spend it.
Let’s look at a simplified example.
Suppose someone needs to spend $100 they don’t have today. They have two options:
1. Borrow $100 from their 401(k), or
2. Wait until they earn and save $100 from their paycheck.
To keep things simple, let’s assume their marginal tax rate is 20%, the 401(k) loan is interest-free, and the 401(k) investments earn zero return.
Scenario 1 (401(k) loan):
They borrow $100 from the 401(k) and spend it. Later, they earn $125, pay $25 in taxes (20%), and use the remaining $100 of after-tax income to repay the 401(k) loan.
Scenario 2 (No loan):
They don’t touch the 401(k). They still need to earn $125, pay $25 in taxes, and use the $100 of after-tax income for the same purchase.
In both cases, the person ends up paying the same amount of tax. The key difference is simply timing: the 401(k) loan gave them access to pre-tax dollars earlier, which they later repaid using after-tax income – just like they would have used to make the purchase anyway.
So, the “double taxation” argument doesn’t really hold up for the principal amount. While the repayment does use after-tax money, the loan itself was made with pre-tax funds, and that offsets the effect. You’re not taxed twice on the same dollars, except perhaps the interest portion which has to be paid using after-tax money and will be taxed again. But that’s a minor amount, plus you are paying interest to yourself, which makes the loan effectively interest-free.
That said, 401(k) loans can have real drawbacks depending on the timing, like losing potential investment growth while the money is out of the market, liquidating funds when market is down, and the risk of triggering taxes and penalties if you leave your job before fully repaying the loan. Those are valid concerns. But the “double tax” rationale isn’t one of them.
What do you think—does this reasoning make sense to you, or is there something I’m missing?
Thanks in advance!
“For one, if you borrow from your 401(k) and instead of spending the money, use it to repay pay-off the loan quickly”.
I have to ask, if they didn’t spend the money why take the loan?
Sorry I was unclear. That example is to illustrate the misconception, not a real-life scenario.
Take it from a 401k Subject Matter Expert: Loan interest is never double-taxed.
Let’s start at a different point. When you need liquidity, and you don’t have cash lying around, you either borrow from a commercial source or from your 401k. If you borrow from a commercial source, the interest you pay may or may not be tax deductible, depending on the purpose. You certainly don’t get that interest back at a later date.
You won’t borrow from the 401k if the commercial loan provides a better value. And, you won’t borrow commercially if the 401k offers a better value.
In fact, given all of the credit card debt in America, payday loans, etc., there are many studies that suggest Americans should borrow more from their 401k to retire those debts.
So, think of your 401k as the Bank of Sanjib:
Done right, repaid in full, a plan loan will improve both your household wealth and your retirement preparation.
First, when you take a loan, it is secured with assets in your 401k. That means that the assets are converted from whatever investment you had into a fixed income investment, like a bond (same as a bank). The fixed income rate of return is the interest rate you pay.
So, first step. Because the principal never leaves the plan, it becomes a fixed income investment, you should examine your asset allocation after the loan is made to ensure you haven’t deviated from your investment strategy.
Second, the interest you pay on your 401k loan may be tax deductible. If the loan is secured with a home mortgage (where interest is otherwise deductible), or starting in 2025 through 2028, new tax code section 6055AA may allow for an “above the line” tax deduction of interest on a loan secured by a lein on a qualified passenger vehicle.
Third, unlike the bank, where interest you pay on a bank loan is always taxable income, the taxation of the interest you pay can be either taxable monies when distributed or tax free:
But to answer your initial question, the interest isn’t double taxed.
The interest you pay on the loan is treated the same as it would be for any other loan – it is either tax deductible or it isn’t.
The interest you receive at distribution is not the same interest. It is treated the same as any other dollar of interest you earned on your 401k investments.
The challenge is that most plan sponsors and their recordkeepers think of 401k loans as leakage. Most recordkeepers haven’t updated their processing to 21st Century functionality – they still require payroll deduction, which is so 20th Century.
Most everyone reading this post already pays at least one bill electronically.
Why not your 401k loans?