The crypto basis trade explained: ETFs, CME futures and funding

What the basis trade is

In futures markets, the basis is the difference between a futures price and the spot price of the same asset. When futures trade above spot (a condition called contango), an investor can buy the asset today, sell a futures contract for later delivery, and lock in that difference as a return. This is known as a cash-and-carry trade.

The position is designed to be market neutral. If bitcoin rises, the spot holding gains and the short futures position loses by roughly the same amount, and the reverse holds if bitcoin falls. What remains is the spread, which converges toward zero as the futures contract approaches expiry, because at settlement the futures price must equal the reference spot price.

The same structure has been run for decades in Treasuries, equity indices and commodities. Bitcoin has historically offered a wider spread than those markets because demand for leveraged long exposure through futures often exceeds the supply of capital willing to sell it.

How it works with spot ETFs and CME futures

Before January 2024, a fund running the trade in the US had to hold bitcoin directly, which raised custody and compliance hurdles for many managers. The launch of US spot bitcoin ETFs changed that. A hedge fund can now hold an ETF share in a normal prime brokerage account and short CME Group bitcoin futures against it, keeping both legs inside regulated venues.

The pairing is tight because of benchmarks. CF Benchmarks notes that several large spot ETFs value their holdings using the CME CF Bitcoin Reference Rate New York variant, while CME futures settle on the London variant of the same rate, which narrows the tracking gap between the two legs.

Annualized basis is the standard way to compare the return with other uses of cash:

• Formula. Annualized basis equals (futures price divided by spot price, minus 1), multiplied by (365 divided by days to expiry).
• Hypothetical example. If spot is $86,000 and a futures contract 90 days out trades at $87,060, the gap is about 1.23%, or roughly 5% annualized.
• The real hurdle. The trade only makes sense if that figure beats the yield on Treasury bills plus financing, margin and execution costs. With the Fed funds target range at 3.75% to 4.00% after the September 16, 2026 hike, a 5% basis leaves a thin margin.

Funding rates on perpetual futures

Offshore exchanges and some US venues also list perpetual futures, contracts with no expiry date. Instead of converging at settlement, perpetuals stay close to spot through a funding rate: a periodic payment, usually every eight hours, between longs and shorts. When the perpetual trades above spot, longs pay shorts.

A trader who holds spot and shorts a perpetual collects that funding while it stays positive, which is the perpetual version of the basis trade. The income is variable rather than locked in, and the rate can turn negative in a sell-off. Bitwise reported that the 7-day average bitcoin perpetual funding rate was about 4.0% annualized in the week to October 5, 2026, down from 4.3% the week before, which it described as contained leverage.

Who runs it and how big it has been

The main participants are multi-strategy and macro hedge funds, relative-value desks and some proprietary trading firms. In CFTC Commitments of Traders data, their activity tends to show up as large short positions held by the leveraged funds category on CME bitcoin futures. The table below tracks how the trade has expanded and contracted.

The pattern is clear: when bitcoin rallies and leveraged demand is strong, the basis widens and capital floods in. When prices fall and the spread approaches the Treasury bill rate, the capital leaves.

How it shows up in ETF flows and 13F filings

Because the long leg is often an ETF share, basis activity moves ETF flow data. Inflows can reflect funds opening hedged positions, and outflows can reflect funds closing them, with no change in anyone’s directional view. 21Shares reported about $2.7 billion of US spot bitcoin ETF inflows in the week to September 25, 2026, the largest week since early October 2025; flow data alone cannot say how much of that was hedged.

Quarterly 13F filings, which US managers with more than $100 million in listed equities file with the SEC, show the ETF leg but not the short futures leg, because futures are not reportable on a 13F. A hedge fund listed as a large IBIT holder may therefore be close to flat on bitcoin. Q2 2026 filings, reported in August 2026, showed Brevan Howard cutting its ordinary IBIT shares by about 70%, from 24.3 million to 7.2 million, and Graham Capital cutting by about 72%, consistent with a lower-return basis environment. Some filers, such as Citadel, also reported large IBIT options positions, which further blurs the directional reading. Q3 2026 filings, due in mid-November 2026, are the next read, best paired with weekly CFTC data on leveraged funds’ CME shorts.

Risks to understand

• Margin and liquidity. The short futures leg is marked to market daily. A sharp rally creates futures losses that must be met in cash immediately, even though the matching ETF gain is unrealized. Funds that cannot post margin may be forced to close.
• Basis collapse. The return is fixed only if the position is held to expiry. If the spread narrows early, a fund rolling contracts or exiting early earns less, and a negative basis can turn the carry into a cost.
• Crowded unwinds. When many funds exit together, they sell ETF shares and buy back futures at the same time. That can produce heavy ETF outflows that look like bearish selling and can add short-term pressure to spot prices.
• Funding variability. Perpetual funding resets every few hours, so income can disappear or reverse without warning, and offshore venues add counterparty and jurisdiction risk.
• Leverage and financing. Thin spreads are usually levered to reach target returns, which magnifies the effect of any of the risks above.

This guide is educational and is not investment advice.

Sources and further reading

• CF Benchmarks: Revisiting the bitcoin basis (October 16, 2025)
• The Block: CME bitcoin futures activity slumps to 14-month low as basis trade unwinds (April 9, 2026)
• CoinDesk: CME loses top spot to Binance in bitcoin futures open interest (December 22, 2025)
• Bitwise Crypto Market Compass, week 41 2026 (October 5, 2026)
• CryptoSlate: Q2 2026 13F filings on bitcoin ETF holders (August 19, 2026)
• CFTC Traders in Financial Futures report (weekly)