The Treasury Basis Trade: How Hedge Funds Earn the Spread and Why It Can Break

In June 2026 a Federal Reserve note estimated that hedge funds’ Treasury cash-futures basis trade had grown to about $830 billion as of September 2025, roughly double its previous peak in early 2020, and that hedge funds were borrowing $3.0 trillion in repo. Most days this trade is invisible plumbing that helps keep Treasury futures and bonds in line. In March 2020 its unwinding became part of the stress in the world’s deepest bond market, and the Fed stepped in with at least $500 billion of Treasury purchases. If hedge fund leverage is new to you, start with gross vs net exposure, then come back here.

What is the Treasury basis trade?

The Treasury basis trade is a long position in a cash Treasury note paired with a short position in the matching Treasury futures contract, with the note financed by borrowing in the repo market. The fund earns the gap between the two prices as they converge.

The “basis” is the difference between the futures price and the cash price of the bonds deliverable into the contract. At delivery the two must meet. If the futures contract is rich, a fund that owns the bond and sells the future locks in that gap, minus what it costs to finance the bond until delivery. The Fed’s 2023 note by Barth, Kahn and Mann (FEDS Notes) describes it the same way and stresses that only the cash leg needs repo financing, because the futures leg needs only margin.

Why does the cash-futures basis exist?

The basis exists because asset managers want long Treasury exposure through futures, and someone has to sell them those futures. Hedge funds take the short and hedge it by buying the cash bond.

Pension funds, insurers and bond mutual funds use futures to add duration without tying up cash. That steady demand pushes futures slightly above the cost of buying the bonds outright and financing them. The Fed’s 2023 note found the rise in hedge fund short futures was paired with growth in asset manager long futures, and suggested that higher rates may have increased asset managers’ hedging demand. The CFTC’s weekly Traders in Financial Futures report shows this split directly: “asset manager/institutional” (pensions, endowments, insurers, mutual funds) on one side, “leveraged funds” (hedge funds and CTAs) on the other. An earlier Office of Financial Research working paper by Barth and Kahn found that a replicating portfolio of bills and futures had been overvalued relative to notes and bonds, and that the trade grew after 2016 to as much as half of all hedge fund Treasury positions and about a quarter of dealers’ repo lending.

How is a basis trade financed with repo?

The fund buys the note, lends it as collateral in a repurchase agreement to borrow almost all of the purchase price, and sells futures against it while posting initial margin. Its own capital covers only the repo haircut and the futures margin.

Each leg has a different counterparty and a different way to fail. The repo lender, usually a dealer bank or a sponsored repo program, can raise the haircut or refuse to roll the loan, since much of this funding is overnight. The futures clearinghouse can raise initial margin, which it does when volatility rises. And the cash bond and futures can move apart before delivery, creating mark-to-market losses that must be paid in cash even though the trade will converge eventually. The Fed noted that hedge fund sponsored repo borrowing rose from $114 billion to $233 billion between October 2022 and May 2023, as short futures in the 2-, 5- and 10-year contracts climbed by $411 billion to nearly $715 billion. That approached the July 2019 high of $750 billion.

How does a basis trade make money? A worked example

It earns the spread between the financing rate implied by the futures price and the actual repo rate, multiplied by leverage. The spread is small, so leverage does the work.

Unlevered, the same trade on $50 million would earn $37,500 a quarter, which is why nobody runs it that way. The fund here is 20 times levered on its equity. That is modest next to the futures-margin leverage the BIS measured, discussed below, and it shows the core trade-off: the more of the cushion you deploy, the higher the return and the smaller the shock you can survive.

How much leverage do basis trades use?

Very high. The BIS Quarterly Review estimated average margin leverage on Treasury futures, the contract value divided by initial margin, at about 175 times for five-year and 120 times for ten-year contracts before the pandemic.

Leverage fell after 2021 because exchanges raised margins as volatility rose, not because funds chose to borrow less. The BIS called the build-up a vulnerability worth monitoring because disorderly deleveraging could set off margin spirals. The latest Fed note, by Monin (June 2026), uses SEC Form PF data and finds hedge funds’ gross Treasury exposure doubled between 2023 and September 2025. For how gross and net figures like these are built, see gross vs net exposure.

What happens when a basis trade unwinds?

An unwind happens when the fund can no longer fund its margin and haircuts, so it sells the cash bonds and buys back the futures, which pushes the cash price down further and hurts everyone else in the same trade.

Run the shock on the example. Volatility jumps. Cash notes cheapen against futures by half a point, a $5 million mark-to-market loss. The clearinghouse lifts initial margin from 2% to 3%, which needs another $10 million. The repo lender lifts the haircut from 1% to 3%, another $20 million. The trade now needs $65 million against $50 million of equity. With $45 million left after the loss and 6% now required per dollar of position, the fund can carry only $750 million and must sell $250 million of notes immediately. Every fund in the same trade faces the same arithmetic on the same day. The BIS documents that large initial margin increases preceded sudden position closures in August 2019 and March 2020, when futures prices jumped and the cash-futures basis inverted.

What happened in March 2020 and April 2025?

In March 2020 basis positions were sold in size as Treasury liquidity collapsed. In April 2025 the documented stress was in a related trade, swap spreads, while the basis trade itself kept growing.

The OFR working paper found that in March 2020 Treasury illiquidity during the pandemic shock led hedge funds to sell large basis trade positions, but concluded the unwind was likely a consequence rather than the primary cause of the stress, and that prompt Fed intervention may have kept it from accelerating. On March 15, 2020 the FOMC said it would increase its holdings of Treasury securities by at least $500 billion and agency mortgage-backed securities by at least $200 billion to support smooth market functioning. The Fed’s 2023 note adds that hedge fund short futures fell more than asset manager longs after March 2020 and took longer to recover.

For April 2025, the June 2026 Fed note reports notable stress after the tariff announcements in the swap spread arbitrage trade, where about $60 billion unwound rapidly in April and a further $40 billion in May, with positions back to about $305 billion by September 2025. The cash-futures basis trade reached about $830 billion over the same period.

How are the Fed and SEC responding to basis-trade risk?

The main structural response is central clearing of Treasury cash and repo trades, so margin is set and collected consistently instead of bilaterally.

The SEC adopted its Treasury clearing rule on December 13, 2023 (press release 2023-247). It requires covered clearing agencies to have members clear eligible secondary-market Treasury cash and repo transactions and to calculate house and customer margin separately. The original deadlines were December 31, 2025 for cash and June 30, 2026 for repo. The SEC extended both by a year; its implementation page, updated in October 2026, lists December 31, 2026 for cash and June 30, 2027 for repo. Clearing repo matters for the basis trade because the repo leg is where most of its funding sits. On the Fed side, the 2020 episode showed it will buy Treasuries to restore functioning; how far that support should extend to levered trades remains a policy question.

How can you track basis-trade risk?

Watch positioning, margins and repo together. Each is a weak signal alone; together they tell you whether the trade is large, getting more expensive to hold, and starting to unwind.

The CFTC publishes positions as of each Tuesday every Friday at 3:30 p.m. Eastern, so leveraged funds’ Treasury futures shorts tell you size with a lag. Exchange margin notices and spikes in overnight repo rates are faster. Cash Treasuries cheapening sharply against futures or swaps is the clearest sign an unwind is under way, though that needs dealer data most individuals don’t have. Bond moves matter for equities through yields as well; our guides to rising bond yields and stocks and the yield curve cover that link, and global macro strategy explains how other funds trade rates.

What does basis-trade stress mean if you hold concentrated stock?

For an executive or tech employee with a large single-stock position, basis-trade stress is a liquidity warning, not a bond trade. When the safest market is forced to sell, everything that depends on liquidity reprices at once.

In a dash for cash, funds sell what they can, and liquid large-cap stocks are among the first. Option prices rise just as you might want protection, so hedges bought in calm markets, such as a put or collar, are far cheaper than hedges bought during the stress. If you borrow against your shares, a sudden rise in yields and a falling stock can combine into a margin call on you, the same mechanics shown in the example above; keep loan-to-value low enough to survive both. And if you hold Treasuries as your safe bucket, prefer bills or short notes you can hold to maturity, so a temporary price dislocation never forces a sale.

The lesson carries over: leverage that is safe at the end is not always safe along the way, and a concentrated position is leverage to one company. Size, hedge and diversify it on a plan.

What is a checklist for monitoring the basis trade?

1. Check leveraged funds’ Treasury futures shorts in the CFTC TFF report each Friday.
2. Note any exchange margin increases on Treasury futures.
3. Watch overnight repo rates for spikes, especially at month-end and quarter-end.
4. Read the Fed’s Financial Stability Report and FEDS Notes for updated Form PF estimates.
5. Track the SEC clearing deadlines: December 31, 2026 (cash) and June 30, 2027 (repo).
6. Price hedges on concentrated stock while volatility is low, not after funding stress starts.
7. Keep any securities-backed borrowing small enough to survive a stock drop and a rate spike together.

Frequently asked questions

Key takeaways

1. The basis trade owns a cash Treasury, shorts the futures and funds the bond in repo, earning a small convergence spread.
2. It exists because asset managers want long duration through futures and hedge funds are paid to take the other side.
3. Leverage is the point and the risk: BIS estimated 50 to 175 times margin leverage on futures, and hedge fund repo borrowing reached $3.0 trillion by September 2025.
4. The trade breaks when futures margins and repo haircuts rise together, forcing funds to sell Treasuries into a falling market.
5. Fed and OFR research treats the March 2020 unwind as a consequence of stress that amplified it, not the root cause.
6. Central clearing of Treasury cash and repo trades, now due December 2026 and June 2027, is the main structural response.
7. For concentrated stockholders, Treasury-market stress is a liquidity signal: it can hit stocks and hedges at the same time.

Sources and method

1. Federal Reserve, Monin, Decomposing Hedge Funds’ U.S. Treasury Exposures (FEDS Notes, June 22, 2026) — basis trade about $830 billion, swap spread unwind in April 2025, $3.0 trillion repo borrowing
2. Federal Reserve, Barth, Kahn and Mann, Is the Basis Trade ‘Back’? (FEDS Notes, August 30, 2023) — trade mechanics, hedge fund shorts, asset manager longs, sponsored repo
3. BIS Quarterly Review, Margin leverage and vulnerabilities in US Treasury futures (September 2023) — margin leverage estimates, margin-driven deleveraging
4. Office of Financial Research, Barth and Kahn, Hedge Funds and the Treasury Cash-Futures Disconnect (Working Paper 21-01, April 2021) — basis trade share of hedge fund positions and dealer repo; March 2020
5. Federal Reserve, FOMC statement, March 15, 2020 — purchases of at least $500 billion of Treasuries
6. SEC, Treasury Clearing Implementation — compliance dates December 31, 2026 (cash) and June 30, 2027 (repo)
7. SEC press release 2023-247 — Treasury clearing rule adopted December 13, 2023
8. CFTC, About the Commitments of Traders Reports — Tuesday positions released Friday at 3:30 p.m. ET; leveraged funds and asset managers in the TFF report

Chart 2 and the worked example are illustrative Proflex math with round, hypothetical inputs (a $1 billion position, $50 million of equity, 1% repo haircut, 2% futures margin, a 0.30 percentage point financing spread); they are not estimates of any real fund. They ignore the futures conversion factor and delivery options, which matter in practice. Charts 1 and 3 are Proflex diagrams and judgments. Position sizes, leverage and dates are from the Federal Reserve, BIS, OFR, SEC and CFTC pages listed.