Asset Placement — What Belongs in a Roth

Asset allocation is the mix of stocks, bonds, and alternatives you own. Asset location — the quieter sibling — is which of those holdings sit in which account. Roth, Traditional, and taxable each tax returns differently, so putting the right sleeve in the right wrapper typically adds 15–60 basis points of after-tax return per year without changing a single underlying holding. Over 30 years at a 5% compound rate, that is roughly 5–20% of terminal wealth, permanently.

The academic literature on asset location is mature. Bergstresser and Poterba (NBER 9268, 2004) documented meaningful location inefficiency in U.S. household portfolios. Dammon, Spatt, and Zhang (Journal of Finance, 2004) derived the optimal location rule under stochastic returns: hold the asset whose return is taxed most heavily in the account that shields it most. Vanguard’s Advisor’s Alpha framework assigns location roughly 0–75 bps of annual value depending on a household’s mix. None of this is controversial. What is controversial — or at least underdiscussed — is how much the conventional wisdom changes once you model the actual tax rates, the qualified-vs-ordinary distinction, and the drag that each specific sleeve generates.

The mental model in one sentence

Every asset class produces three streams of return: price appreciation (taxed as long-term capital gains when realized), qualified dividends (taxed at LTCG rates annually), and ordinary-rate distributions (taxed at your marginal income rate annually). Holding an asset in a taxable brokerage account causes you to pay tax on each year’s ordinary and qualified distributions, year after year, forever. Holding the same asset in a Roth IRA eliminates that drag entirely. Holding it in a Traditional IRA defers the drag but converts the eventual withdrawal to ordinary-income tax. The location question reduces to: which sleeves benefit most from the Roth’s permanent shelter, and which benefit most from the Traditional’s deferral?

The ranking, from “always Roth” to “always taxable”

If you rank asset classes by annual tax drag in a taxable brokerage account — assuming a 32% federal ordinary rate, 15% LTCG rate, and 5% state tax — the ordering collapses into a few clean tiers.

Tier 1 — Highest drag, shelter first

REITs, high-yield bonds, preferred stocks, and actively-managed high-turnover equity funds. REITs distribute non-qualified dividends taxed at ordinary rates; a REIT yielding 4% costs roughly 1.48% per year in a 32% bracket with 5% state tax. On $100,000, that is $1,480 per year — and compounded at 5% over 30 years, the opportunity cost exceeds $98,000. If you must hold REITs, hold them in a Roth or Traditional IRA. High-yield bonds, bank loan funds, and taxable corporate bond funds behave similarly.

Tier 2 — High drag, Traditional is acceptable

Aggregate bond funds, TIPS, and cash/money-market. Investment-grade bonds yielding 4.5% produce roughly 1.67% annual drag in the same tax bracket. TIPS generate “phantom income” — the inflation-adjusted principal is taxable annually even though the investor does not receive it in cash — which makes them particularly punishing in taxable. These belong in tax-deferred accounts. A Traditional IRA is actually ideal: you get full deferral, and when bond coupons eventually come out as ordinary income in retirement, that matches their underlying tax character anyway.

Tier 3 — Moderate drag, depends on yield

International developed equities (higher qualified dividend yield, ~2.5%), emerging-markets equities (~2.3%), and corporate investment-grade bond funds. International sleeves carry a wrinkle: if you hold them in a taxable account, you can claim the foreign tax credit (FTC) for withholding already paid, which recoups roughly 20–30 bps of the drag. Holding international in an IRA forfeits that credit. For larger international allocations, the FTC recovery often tips the balance toward taxable placement.

Tier 4 — Low drag, Roth-or-taxable

Broad U.S. stock index funds (VTI, ITOT, VOO). A total-market index fund yields ~1.3% in qualified dividends with negligible turnover. In the same 32% bracket, annual drag is ~0.28%. Because broad equity index funds generate low current income and gains are deferred until sale, they are the most tax-efficient sleeve to hold outside a Roth. That said, if your Roth is small relative to taxable, fill Roth with equities anyway: the higher expected return makes the Roth shelter more valuable than sheltering a lower-return bond sleeve, even with heavier drag on the bond.

This last point is where most simple “bonds in 401(k), stocks in brokerage” heuristics go wrong. Dammon-Spatt-Zhang’s result generalizes: when tax-deferred space is scarce relative to the portfolio, high-expected-return assets earn the Roth seat, not high-drag assets. Our tool implements this correctly by ranking each sleeve on expected_return − drag rather than drag alone.

Three edge cases that break simple rules

Municipal bonds don’t belong in a Roth

Munis are already tax-free at the federal level (and often at the state level for in-state bonds). Placing them in a Roth wastes the tax-free shelter on an asset that is already sheltered, while the Roth’s after-fee yield is lower than a taxable corporate bond at equivalent credit quality. If you are in a bracket where munis make sense, hold them in taxable.

Master limited partnerships (MLPs) break inside IRAs

MLP distributions generate unrelated business taxable income (UBTI). Once UBTI exceeds $1,000 in an IRA, the IRA itself owes tax — filed on Form 990-T by the custodian — and the positions you thought were tax-sheltered become double-taxed. Keep MLPs in taxable.

I Bonds are better in taxable

Series I Savings Bonds (via TreasuryDirect) already offer federal tax deferral on accrued interest until redemption, and they cannot be held inside an IRA. They belong in the non-IRA side of the portfolio by construction.

How much does location actually save?

For a portfolio of $500,000 split 60% equities / 30% bonds / 10% REITs, with 20% of the dollars in a Roth, 30% in Traditional, and 50% in taxable, and taxed at 32% federal + 5% state, an optimally located portfolio saves approximately 30–50 basis points per year of drag versus a naively-blended allocation. That translates to roughly $1,500–$2,500 per year, or $95,000–$165,000 compounded over 30 years at 5%. The savings scale roughly linearly with portfolio size and with the spread between your ordinary and LTCG rates.

Run your own numbers in the Asset Location Architect — the tool outputs annual savings, basis-point improvement, and compounded value side-by-side.

Rebalancing across accounts without wrecking the tax plan

Optimal location and optimal rebalancing can fight each other. If bonds have rallied and equities have lagged, a simple rebalance would sell bonds to buy equities. If your bonds all sit in a Traditional IRA and equities in taxable, you can rebalance inside the IRA without triggering a single taxable event. This is the second-order payoff of good location — your rebalances become tax-free by default. When you run out of tax-deferred room to rebalance, prioritize in this order: (1) direct new contributions to the under-weighted sleeve in whichever account has room, (2) reinvest distributions into the under-weighted sleeve, (3) rebalance inside IRAs, (4) only as a last resort, realize gains in taxable — and even then, harvest losses to offset.

What the tool does not model (yet)

Our Asset Location Architect assumes steady-state holdings and does not account for: (1) tax-loss harvesting in taxable, which partially offsets drag by creating deductible losses; (2) the step-up in basis at death, which eliminates all unrealized gains in taxable for your heirs and meaningfully reduces the cost of holding low-turnover equities there; (3) state tax arbitrage for investors planning to relocate between high-tax and no-tax states; and (4) NIIT (3.8%), which applies to investment income above MAGI thresholds ($200K single / $250K MFJ) and effectively raises the drag for higher earners by another ~38 bps on ordinary-rate distributions. In practice, (1) and (2) strengthen the case for equities in taxable, while (4) strengthens the case for all yield-bearing assets inside an IRA.

FAQ

Does the same logic apply to a Roth 401(k) vs. Traditional 401(k)?

Yes. A Roth 401(k) functions identically to a Roth IRA for location purposes — contributions grow tax-free, qualified withdrawals are tax-free. Traditional 401(k) functions identically to a Traditional IRA. The choice between the two (Roth 401(k) vs. Traditional 401(k)) is a contribution-timing question covered in our Roth 401(k) Rules article. Asset location is about what sits inside whichever account you already have.

What about HSAs?

HSAs are triple-tax-advantaged — pre-tax contribution, tax-free growth, tax-free qualified medical withdrawal — which makes them the single most tax-efficient account type in the U.S. code. Treat an invested HSA the same as a Roth for location purposes. If the HSA can also function as a retirement account (spending kept low, receipts saved), fill it with the highest-expected-return sleeve.

Should I own different funds in different accounts, or the same fund spread across all three?

Different. The whole point of location is that the same asset class belongs in different accounts depending on tax treatment. Owning the same total-market index fund across your Roth, Traditional, and taxable is a missed opportunity — you could be holding a tax-efficient equity index in taxable, a bond fund in Traditional, and a REIT or EM fund in Roth, and coming out ahead by 30–60 bps per year.

How often should I re-optimize location?

Once at initial setup, and then whenever your circumstances change meaningfully — a promotion that pushes you into a new marginal bracket, a move to a different state, retirement, or a large inheritance. Day-to-day rebalancing should happen within the existing location — do not “chase” the optimal ranking if doing so requires realizing gains in taxable. The friction of a 15–20% LTCG bill usually dominates the 30–60 bps optimization gain.

Key takeaways

• Location is worth 15–60 bps per year, compounding to roughly 5–20% of terminal wealth over 30 years.
• Rank by expected return minus drag, not drag alone. When Roth space is scarce, the highest-return sleeves earn it.
• REITs, high-yield bonds, and TIPS go in IRAs — their ordinary-rate distributions bleed badly in taxable.
• Broad U.S. stock index funds are the most tax-efficient taxable sleeve.
• International equities earn a partial pass for taxable placement because the foreign tax credit is only available there.
• Munis, MLPs, and I Bonds belong in taxable by construction.

---

Reviewed against Vanguard’s Advisor’s Alpha (2023 update), Bergstresser & Poterba (NBER WP 9268), and Dammon-Spatt-Zhang (Journal of Finance Vol. 59, No. 3, 2004). Educational content only — not tax, legal, or investment advice.