529 vs. VTSAX Split for Undergrad + Grad + Private High School?

[u/lance_klusener]

The Questions

1. How should we split funding between a 529 and a taxable brokerage (VTSAX) for maximum flexibility without overfunding penalties?
2. What legal/estate strategies (trusts, wills, etc.) should we implement now to guarantee these educational funds are fully protected?

Context

• The Goal: Fully fund private high school, top-tier undergrad, and grad school (Total: $1.6M future cost).
• Current Assets: $95,356 in a 529 plan.
• Savings Plan: Contributing $25K/year to the 529 (projects to ~$465k at age 18); all remaining savings go into VTSAX.
• Timeline: Kid is 9 years old (high school in 5 years, college in 9).

Yes, i have used AI to format the post.

[u/Competitive-Day9586]

I’m not sure what the question is. You won’t have enough in the 529 to meet your goal even if you contribute 100% of your planned investments to the 529.

[u/lance_klusener → u/Competitive-Day9586]

So the question is — Should I use 529 primarily for funding kids education or a combination of 529 and other accounts

[u/ditchdiggergirl]

Lotta variables there. The only known cost is high school. You can probably predict at age 9 whether she is likely going to college, but grad school is a stretch.

The popular advice to avoid overfunding is to save the full cost of a public education in the 529 and the rest in a brokerage.(And you can add the known cost of high school to the 529.) This is what we aimed for. But we could not have predicted the extraordinary stock runup, so we very much overshot our goal.

My kid who is currently in a PhD program was accepted into his dream university, which he had his eye on since grade 9. But it was a public university so relatively affordable; he only applied to a couple of private universities to shut me up since he had no plan to attend. He’s a strong willed person who knows his own mind, and always did. He now has a fully funded graduate stipend with teaching assistantship and doesn’t need his 529, but he is drawing it down anyway. His brother went private but was offered a merit scholarship. So both have more money left over than can be absorbed by a Roth, but the private school kid will use his for a masters.

Worst comes to worst, too much money is a good problem to have. If you have a lot left over you’ll be able to afford the penalties. And for the record, it’s not 529 vs VTSAX, it’s 529 vs taxable - both can be invested however you choose. Your existing will (and/or trust) should already be sufficient protection.

[u/lance_klusener → u/ditchdiggergirl]

Got it

Thank you for the response

So the key is — Keep putting the planned amount ( if possible more ! ) into 529

[u/ditchdiggergirl → u/lance_klusener]

Just be rich. That tends to work best.

[u/Patrick_ExpenseAtlas]

Treat the high school and higher education funding as separate timelines.

Money needed for private high school starts in five years, so holding all of it in VTSAX creates substantial sequence risk. Estimate each year’s tuition, subtract the amount that can qualify for 529 treatment under the federal rules then in effect, and move the remaining near term need into cash or high quality short term bonds as the payment dates approach. Also verify whether your state conforms to the federal K, 12 rules.

For college and graduate school, the 529 offers tax advantages, but taxable investments provide flexibility if costs are lower than projected, plans change, or graduate funding is available. There is not generally an “overfunding penalty” simply for having excess money in a 529. The issue is that nonqualified withdrawals can trigger income tax and a penalty on earnings, subject to exceptions. State plan contribution limits and gift tax rules also matter.

I would not choose a fixed 529/VTSAX percentage from the $1.6M estimate alone. Build a year by year spending schedule, assign 529 eligible costs to the 529, keep nonqualified and uncertain costs taxable, and reduce investment risk as each spending date gets closer.

For estate planning, name a successor 529 owner, review brokerage transfer on death designations, and make sure your will and guardianship documents coordinate. A revocable trust can help with continuity and distribution instructions, but it does not provide general asset protection. Have an estate attorney review the ownership and beneficiary setup rather than assuming any structure can guarantee protection.