Should I Keep Funding My 529 in October 2026? 5 Break-Even Tests When Mortgage Rates Top 7% and Stocks Are Running Hot
On October 1, NerdWallet's "Mortgage Rates Today, Thursday, October 1: Rates Rise Sharply" warned that house hunters were getting an early dose of October sticker shock. Its weekly roundup, "Weekly Mortgage Rates Find a New Normal Above 7%," adds that it's OK to reevaluate your homebuying plans during the slow fall and winter months. If you also fund a 529, that headline probably raised a quiet question: should the $600 a month going to a college account go somewhere that feels more urgent?
I ran the numbers on my own 529 decisions before I started helping friends with theirs. The headline turned out to be the least useful input. Five tests decide whether to keep funding, trim, or switch plans, and each has a break-even number you can check against your own life. Below I work all five through one example household, then show where your numbers would change the answer.
The Example Household (An Illustration, Not Your Situation)
- Two kids, ages 4 and 9, so 14 and 9 years until each turns 18
- $300 a month per child, stopping at 18: $50,400 for the younger, $32,400 for the older, $82,800 total
- Assumed 6% gross annual return, compounded monthly (an assumption, not a forecast)
- Home-state plan at a 0.75% expense ratio vs. an out-of-state plan at 0.15%
- Hypothetical state income tax of 5% with a deduction on up to $10,000 a year
Change any one of these and the answer can flip. That's the point of running the tests.
Test 1: The Recurring-Fee Test (the IHG $350 Logic)
NerdWallet's "Is the New IHG Premium Card Worth Its $350 Fee?" makes a simple point. If you already plan to stay at IHG hotels this year, you have a strong reason to hold the card. If you don't, the fee is just a fee. A 529 expense ratio is the same kind of cost, except it never appears as a line item on a statement.
Here is what the 0.60-point gap does to the example household (net returns of 5.85% vs. 5.25% after fees):
| Low-fee plan (0.15%) | Higher-fee plan (0.75%) | Gap | |
|---|---|---|---|
| Younger child (14 yrs, $300/mo) | $77,768 | $74,204 | $3,564 |
| Older child (9 yrs, $300/mo) | $42,513 | $41,304 | $1,209 |
| Both children | $120,281 | $115,508 | $4,773 |
By year 14, the younger child's balance is near $75,000. At that size a 0.60-point gap costs about $450 a year, which is more than the $350 IHG fee, and nobody mails you a bill for it.
The useful question isn't "is 0.75% too high?" It's "what am I getting for the extra 0.60 points?" Usually the answer is a state tax deduction, which is Test 2. For a longer look at fee drag, see 529 Plan Hidden Fees: How a 0.75% Expense Ratio Difference Costs $16,500 Over 18 Years.
This is the kind of analysis Nelovanti runs for you, so you don't have to build the spreadsheet yourself.
Test 2: The State-Deduction Test (Does the Refund Beat the Fee Gap?)
In the example, $7,200 a year of contributions is fully deductible under the $10,000 cap. At a 5% state rate that's a $360 refund a year for the nine years both kids are funded, then $180 a year for the five years only the younger child is funded. (Yes, $360 is suspiciously close to the IHG fee. A coincidence, but a handy one to remember.)
Total refunds are $4,140 undiscounted. If you reinvest each refund in the 529 at the higher-fee plan's 5.25% net return, they grow to about $6,180 by year 14. That's a simplification, since it pools both kids' refunds. Against the $4,773 fee gap:
| State marginal rate | Reinvested refunds (year 14) | Minus $4,773 fee gap | In-state plan vs. low-fee plan |
|---|---|---|---|
| 3.0% | $3,708 | −$1,065 | Low-fee plan ahead |
| ~3.9% | ~$4,773 | $0 | Break-even |
| 5.0% | $6,180 | +$1,407 | In-state plan ahead |
| 6.5% | $8,034 | +$3,261 | In-state plan ahead |
In this example, the break-even is a state benefit worth about 3.9 cents per dollar contributed. Three things move it:
- Your cap. If you contribute more than your state allows you to deduct, the extra dollars earn no refund.
- Parity states. Some states grant the deduction for any state's plan, which makes the low-fee plan the clear winner.
- Recapture rules. Some states claw back the deduction on non-qualified withdrawals.
The full checklist is in In-State vs. Out-of-State 529: The 6-Question Checklist That Decides a $21,600 Difference.
Test 3: The Mortgage-Rate Test (Use Your Rate, Not the Headline)
The NerdWallet headline says "above 7%," but that's the price of a new loan. If you locked 3.5% in 2021, your mortgage isn't what your 529 is competing against.
Here is $300 a month over 14 years (the younger child's horizon). It compares extra mortgage principal against the 529 from Test 2, with 5.85% net return and the 5% state refunds reinvested:
| Your mortgage rate | $300/mo extra principal (14 yrs) | $300/mo into 529 plus refunds | Result |
|---|---|---|---|
| 3.5% | $64,920 | $81,511 | 529 ahead by $16,591 |
| 5.0% | $72,780 | $81,511 | 529 ahead by $8,731 |
| ~6.4% | ~$81,500 | $81,511 | Break-even |
| 7.0% | $85,212 | $81,511 | Mortgage ahead by $3,701 |
The break-even depends on what you assume the 529 will earn:
| Assumed 529 gross return | Break-even mortgage rate |
|---|---|
| 4% | ~4.5% |
| 6% | ~6.4% |
| 8% | ~8.4% |
A 7% mortgage beats this 529 only if you believe the 529 will earn under roughly 6.6% gross. And the two sides aren't equally certain. Paying down a mortgage is a guaranteed return, while 529 returns are a bet. The 529 has its own constraint: non-qualified withdrawals owe income tax plus a 10% federal penalty on the earnings. Home equity has no such restriction, but you can't spend it without borrowing or selling. If you itemize, your mortgage payoff return is also a bit lower than the stated rate.
If you're weighing a house purchase instead (the "reevaluate your homebuying plans" scenario), the competing use of cash is a down payment, not extra principal. Test 4 prices that. For a deeper version of the mortgage comparison, see Should I Put Extra Money Into a 529 or a 7% Mortgage? The 6-Question Checklist.
You can model this for your specific situation at Nelovanti, using your actual mortgage rate, your state's deduction, and your plan's fees.
Test 4: The "Restock, Don't Splurge" Test
NerdWallet's "I Have One Rule for Shopping Amazon Prime Day" describes a rule of no splurging and no regrets, just restocking the stuff you'd buy anyway at a discount. That works as a 529 rule too. The baseline contribution is something you'd do anyway. A scary rate headline, or a market that's up a lot, isn't a reason to change it by itself. A change in one of your inputs is.
Here is what changing it on a reaction costs. Say you pause both kids' contributions for six months to build a down payment. That skips $3,600. Treat it as if it had gone in today and let it grow to the 18th birthdays at 5.85%:
- Younger child: $1,800 × 1.0585¹⁴ ≈ $3,990
- Older child: $1,800 × 1.0585⁹ ≈ $3,003
- Total: up to about $7,000
That is the upper bound, because the skipped contributions would really have been spread over six months. So you'd be trading $3,600 today for roughly $7,000 at college time. It can still be the right trade if the down payment lets you buy a home you've planned for. Price it before you do it, and consider trimming to $300 a month instead of pausing, which roughly halves the cost.
Inputs that justify a change are:
- A fee or deduction difference you hadn't priced in
- A mortgage rate above your break-even
- A shorter timeline
- A change in your income or emergency cushion
A headline alone isn't one of them.
Test 5: The Horizon Test (Where the AI-Bubble Worry Actually Matters)
Mr. Money Mustache's "Will the AI Bubble Destroy our Retirement?" opens with "Wow, how about that stock market?" and observes that people worry both when the market crashes and when it runs to records. I won't weigh in on AI valuations. The 529-specific question is how many years remain until each child's first tuition bill, and that timeline decides how much a drop can hurt.
Here is how long a recovery takes at an assumed 6% return:
| Drop | Gain needed to recover | Years to recover at 6% |
|---|---|---|
| 20% | 25.0% | 3.8 |
| 30% | 42.9% | 6.1 |
| 40% | 66.7% | 8.8 |
In the example, the 4-year-old has 14 years, so even a 40% drop has time to heal if returns average 6%. The 9-year-old has 9 years. That clears a 30% drop but is barely enough for a 40% one. Recovery isn't guaranteed, and the 6% is assumed. When the older child is 5 years out, a 30% drop would likely still be unrecovered at the first bill.
That's why age-based portfolios step down by age, not by market level. The older child's account should de-risk first, while the younger child's can stay aggressive longer. De-risking too early has its own cost: it gives up growth. Should I Move My 529 to Conservative After a Record Stock Run? puts a dollar figure on that for a 4-year-old.
The Five Tests at a Glance
| Test | The question | Example break-even | Example result |
|---|---|---|---|
| 1. Fee | What do the extra expense-ratio points buy? | 0.60-pt gap = $4,773 | Needs a reason, such as a deduction |
| 2. Deduction | Does your state refund beat the fee gap? | ~3.9% state benefit | At 5%, in-state plan ahead by ~$1,407 |
| 3. Mortgage | Is your actual rate above the break-even? | ~6.4% (at 6% 529 return) | At 7%, mortgage ahead by $3,701; at 3.5%, 529 ahead by $16,591 |
| 4. Reaction | Did an input change, or just a headline? | Pausing 6 months = up to ~$7,000 | Keep the baseline unless an input moved |
| 5. Horizon | Do you have more years than the recovery time? | 6.1 years for a 30% drop | Older child de-risks first |
Where Your Numbers Will Differ
The example is built to be checked, not copied. Your answer shifts with:
- Each child's age and current balance. A $40,000 balance changes the math on both fees and risk.
- Your plan's real expense ratio. Plans range from well under 0.20% to over 1%.
- Your state's deduction rate and cap, and whether it only counts in-state plans.
- Your actual mortgage rate and how much of the principal is left.
- Your target per child. Tuition inflation above the default 3% assumption can raise the monthly amount you need. See 529 College Savings Calculator: Why the Default 3% Inflation Assumption Undercounts Your Two-Kid Target by $118,930.
A few honest notes. If your state deduction is small, the low-fee plan probably wins. If your mortgage rate is below about 5%, the 529 usually wins in this setup. If your kids are within about 5 years of college, Test 5 matters more than Tests 1 through 3. And if you're short on emergency savings, none of these tests should come first.
Nothing here has a deadline. A rate headline on October 1 doesn't expire on October 2. The math is the same next week, so you have time to run it with your own inputs.
If you'd like to see all five tests with your own numbers, Nelovanti will compare plans, project both kids' targets, and show the break-even against your actual mortgage rate. Whatever you decide, decide it from your numbers and not from the headline.
Sources
- Is the New IHG Premium Card Worth Its $350 Fee? — NerdWallet
- Weekly Mortgage Rates Find a New Normal Above 7% — NerdWallet
- I Have One Rule for Shopping Amazon Prime Day — and It Saves Me Big — NerdWallet
- Mortgage Rates Today, Thursday, October 1: Rates Rise Sharply — NerdWallet
- Will the AI Bubble Destroy our Retirement? — Mr. Money Mustache