BOXX Mimics Treasury Yields With No Distributions and Lower Taxes, But the IRS Has Started Asking Questions

If you keep cash in a money market fund and pay California’s top marginal rate, you hand roughly half of your yield to two governments before you spend a dollar of it. Alpha Architect 1-3 Month Box ETF (NYSEARCA:BOXX | BOXX Price Prediction) was built to fix exactly that, replicating Treasury bill returns through S&P 500 box spreads while paying no distributions at all. BOXX has $11.4 billion of assets on that pitch, and it has mostly delivered. The same mechanism that makes BOXX tax-efficient is the one the IRS has started circling.

What you are actually buying

A box spread is four options stitched together so the payoff is fixed at expiration. BOXX holds long and short synthetic positions on the S&P 500 with strike prices set so the difference equals roughly the risk-free rate. The fund’s stated objective is to equal or exceed the price and yield performance of the 1-3 month sector of the U.S. Treasury bill market, benchmarked to the Solactive 1-3 Month US T-Bill Index. The expense ratio is 0.19%, cheap for a synthetic strategy and expensive next to a plain bill ETF like iShares 0-3 Month Treasury Bond ETF (NYSEARCA:SGOV) at roughly 0.09%.

The crucial piece is what happens to the gains. BOXX does not pay interest, dividends, or distributions in normal operation. Returns accumulate as price appreciation, and the ETF in-kind redemption mechanism under Section 852(b)(6) flushes embedded gains out of the fund without a taxable event for remaining shareholders. Hold your shares more than a year and you pay long-term capital gains plus the net investment income tax instead of ordinary income on every coupon.

Does it match what a T-bill pays

BOXX returned 4% over the trailing year ending May 22, with shares at $117. Over that same window, 4-week T-bills traded at about 3.6% and 6-month bills at 3.7% as of May 22, 2026. Since inception on December 27, 2022, BOXX has returned 17% cumulatively, tracking the bill curve closely.

The after-tax math is where the case lives. Park $500,000 at 5% in a money market and a California high earner facing roughly a 50% combined marginal rate keeps about $12,500 of the $25,000 in yield. Run the same dollars through BOXX, hold over a year, and the federal long-term capital gains rate plus NIIT trims the tax bill to roughly $5,500 to $7,500. That is $5,000 to $7,000 of annual savings on the same nominal yield.

Where the IRS comes in

The IRS has never blessed this characterization in writing. Standalone box spreads are Section 1256 contracts, which get 60/40 long-term and short-term treatment regardless of holding period. BOXX claims something different: that wrapping the boxes inside an ETF converts the return into capital gains realized only on sale.

White Coat Investor’s Jim Dahle flagged the issue in December 2024, advising investors to wait two to three years to see how the IRS addresses its tax strategy. ETF.com put it more plainly in November 2025, writing that BOXX’s long-term viability hinges on whether regulators will address its tax classification strategy. This is because the entire value proposition relies on tax arbitrage.

In August 2024, BOXX paid an “unintended” taxable distribution. The dollar amount was small, but it showed the structure can leak under stress, and the fund was already near $4 billion in assets when it happened.

Who fits and who does not

BOXX makes sense as a cash sleeve for taxable accounts held by high earners in high-tax states, where the after-tax spread over money markets and SGOV is wide enough to matter and the holding period naturally extends beyond a year. It is wasted inside an IRA or 401(k), where ordinary-income treatment never applies. Plus, it is the wrong tool for emergency cash you might touch in the first 12 months.

Simpler substitutes exist, such as the VMSXX for federal-tax-free municipal money market exposure, SGOV for state-tax-free short Treasuries, and Janus Henderson AAA CLO ETF (NYSEARCA:JAAA) for higher AAA CLO yield taxed as ordinary income. Each gives up something BOXX provides, and none carries the same characterization risk. If the IRS successfully challenges this fund, current and past holders of this ETF face the possibility of a retroactive tax classification. You’re going to have to deal with unexpected tax liabilities plus potential penalties.