He Will Move $500,000 of His 401(k) Into a Bond Fund for Safety. A 1-Point Rise in Yields Can Cut About $30,000 Without a Single Default
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A 64-year-old is about to move $500,000 of his 401(k) out of stocks and into an intermediate-term bond fund. His plan is to retire soon, live on the 401(k) for a few years, and claim Social Security at 67. To him, the switch feels like locking the doors before a storm.
The appeal is easy to understand. Stocks have been volatile, and bonds feel stable by comparison. But the current rate environment adds a wrinkle that is easy to overlook. On September 16, the Federal Reserve raised the top of its federal funds target range to 4%, its first hike in more than three years, and the September dot plot signaled one more increase likely before year-end. Even with higher rates on offer, a bond fund carries a risk that most savers do not see until it shows up on a statement.
How His Bond Fund Can Drop With Every Issuer Still Paying
Bond funds carry two main risks. Credit risk is the chance an issuer stops paying. Interest-rate risk is the chance existing bonds lose value because newer bonds pay more. Even a fund holding only U.S. Treasuries carries the second risk fully.
Say his fund holds bonds paying 4%, and new bonds start paying 5%. The new ones pay more, so nobody will pay full price for the older ones. Their prices fall until the yield becomes competitive. Every payment still arrives on time, and the fund’s share price falls anyway. The 2022 bond market showed this on a large scale, when the Bloomberg US Aggregate Bond Index lost roughly 13% in price as the Fed raised rates by four percentage points over the course of the year.
Duration is the number that explains that math. It measures how sensitive a fund is to rate changes, and it sits on every fund fact sheet. A six-year duration means a one-percentage-point rise in the yields relevant to that fund’s holdings would lower its price by roughly 6%, before interest income. On a $500,000 balance, that translates to about $30,000. A half-point rise would mean roughly $15,000. For context, the Bloomberg US Aggregate Bond Index currently carries a duration of about 5.88 years, above its long-term average of roughly 5 years.
An individual Treasury bond has a maturity date. Hold it to the end, and the government repays full face value regardless of interim price moves. A bond fund keeps replacing bonds as they mature, so there is never a set date when the original balance returns. Target-maturity funds do have an end date, but fees and trading differences mean they cannot promise a specific dollar amount.
Where a Rate Shock Runs Into His Social Security Timing
His plan calls for drawing $3,000 a month as bridge income until age 67. Over three years, that totals $108,000. A $30,000 rate-driven drop equals roughly ten months of those withdrawals.
Higher yields do help over time. As bonds mature, the fund reinvests at new, higher rates, and the growing interest payments can gradually offset the initial price loss. The catch is that recovery has no fixed schedule. His problem is more immediate: he needs cash monthly. If the fund’s distributions fall short of his withdrawals, each share sold at a depressed price is one fewer share compounding at the improved yield later.
The loss alone would not exhaust his bridge funds. The deeper concern is behavioral. Watching a supposedly safe investment fall could tempt him to file for Social Security early to protect the account balance. His full retirement age (FRA) is 67. Filing exactly three years early reduces his benefit by 20%, because the Social Security Administration applies a reduction of 5/9 of 1% for each of the first 36 months claimed before FRA. On a $2,500 monthly benefit, that penalty turns the check into $2,000, a $6,000 annual shortfall before future cost-of-living adjustments (COLAs). Turning 67 does not erase that reduction.
A bond fund can recover from a price drop. A permanently reduced Social Security benefit cannot be undone by reaching a birthday.
His 401(k) Delays the Tax Bill but Leaves Rate Risk Untouched
Moving money between funds inside a 401(k) does not trigger capital-gains tax. That is a genuine advantage. The flip side is that a loss inside the account is not deductible, and traditional 401(k) withdrawals are taxed as ordinary income regardless of what caused the balance to change. The account structure delays income tax, but it offers no shield when yields rise and prices fall.
Five Checks Before He Moves the Money
- Effective duration. This is the number that shows how far the fund could fall per point of rate increase. It belongs on the fund fact sheet.
- What the fund holds. Treasuries, investment-grade corporate bonds, mortgage-backed securities, and lower-quality debt each carry different credit and rate profiles.
- Duration vs. spending date. If he needs the money within three years, a six-year duration does not match that timeline. Short-duration funds or stable-value options inside the 401(k) may be worth comparing.
- Separate buckets. Bridge money earmarked for the next few years could sit in something with much lower rate sensitivity, leaving longer-duration bonds for money he will not touch for a decade.
- Expense ratio. Fees are paid directly out of the interest income he is counting on to offset any price loss.
The bond fund may still fit his plan well. How safe it turns out to be depends on whether its duration matches when he actually needs the money. His most permanent decision, by a wide margin, is protecting the age-67 claim date. Every retiree’s situation is different, so running the numbers for a specific fund and a specific withdrawal schedule is worth doing before the trade is placed.
Editor’s note: This article was updated to reflect the Federal Reserve’s September 2026 dot plot signaling one additional rate hike likely before year-end, the Bloomberg US Aggregate Bond Index’s current duration of approximately 5.88 years, and the Social Security Administration’s two-tiered monthly reduction formula underlying the 20% early-claiming penalty for filing exactly 36 months before full retirement age.
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Gerelyn Terzo is the author of dividend investing handbook "Dividend Investing Strategies: How to Have Your Cake & Eat It Too." A veteran financial journalist, she covers agri-finance for outlets like Global AgInvesting and the broader stock market and personal finance for 24/7 Wall Street. She began at CNBC and later helped launch Fox Business in New York. Gerelyn currently resides in Woodland Park, Colorado and dabbles in nature photography as a hobby.
