Cboe Global Markets recorded an all-time high in S&P 500 box spread trades this month, with investors using the options structure to earn more than they would from Treasuries. The surge comes as Treasury yields climb to their highest levels in decades, a rout that has also pressured stocks including the S&P 500.
Cboe Global Markets reported that outstanding notional value in S&P 500 box spread trades hit $146 billion as of mid-September 2026, an all-time record. The milestone reflects how aggressively investors are seeking alternatives to a deteriorating Treasury market.
Average daily notional trading volume in these box spreads topped $2.3 billion over the prior month, a 26% jump from the same period a year earlier. Retail traders are also active in the segment, averaging $54 million in daily volume.
A yield edge over Treasuries
A box spread combines two calls and two puts at different strikes on the same underlying index, producing an outcome that's fixed regardless of where the market moves — functioning much like a zero-coupon interest rate instrument. Three-month S&P 500 box spreads are currently yielding north of 4.4%, against three-month Treasuries below 4% and the Secured Overnight Financing Rate near 3.9%. That gap works out to roughly 50 basis points more than Treasuries, and the gains may qualify for capital-gains tax treatment rather than ordinary income, improving the after-tax math for certain investors.
ETFs built on the trade near $20 billion
Total assets under management for box-spread ETFs have climbed to roughly $20 billion. Alpha Architect's BOXX fund dominates the category, with about $15 billion in AUM — roughly three-quarters of the entire market. Cboe has also built a Quoted Spread Book, or QSB, to provide electronic quoting and trading for designated box spreads, reducing friction and improving price transparency.
The Treasury rout squeezing stocks
The shift comes as Treasury yields have surged to levels not seen in decades. The 10-year Treasury yield hit 5.15% on Thursday, its highest since 2007. The 30-year bond yield reached 5.442%, its highest level since 2004. Those moves have pressured equities: the S&P 500 and Dow Jones Industrial Average struggled, while the Nasdaq Composite sold off 1% on Wednesday.
Sources: Crypto Briefing, US Top News and Analysis
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