Federal Reserve reports hedge funds’ $830B Treasury exposure driven by basis trade

Hedge funds have quietly built an $830 billion position in one of the oldest arbitrage strategies in fixed income. The Federal Reserve now says that trade is the primary engine behind the sector’s ballooning Treasury market footprint.

A June 2026 FEDS Note, drawing on SEC Form PF data, found that large hedge funds held $2.4 trillion in long US Treasury exposure as of September 2025. The basis trade, a strategy that pairs long cash Treasuries with short futures positions financed through the repo market, accounts for roughly 35% of that figure.

To put the scale in perspective: the $830 billion basis trade position has effectively doubled its pre-pandemic peak from early 2020. That earlier peak, of course, ended with the sort of market seizure that required the Fed to step in as buyer of last resort.

What the basis trade actually is, and why it matters

The basis trade exploits tiny price differences between Treasury bonds and Treasury futures contracts. When a futures contract trades at a slight premium to the underlying bond, hedge funds buy the bond, sell the future, and pocket the spread at expiration.

That leverage comes from the repo market, where funds borrow against their Treasury holdings to finance positions many times larger than their actual capital. The Fed’s data shows repo borrowing by these funds has reached $3.0 trillion. Gross Treasury exposures, combining long and short positions, now total $4.0 trillion, split between $2.4 trillion long and $1.6 trillion short.

The trade enhances Treasury market liquidity and helps keep futures pricing in line with cash bonds. That’s the good news. The less comforting part is what happens when it unwinds quickly.

Concentration risk and Cayman complexity

The Fed’s analysis reveals a market that’s becoming increasingly top-heavy. The 50 largest funds by Treasury exposure now account for roughly 90% of total hedge fund activity in the space, up from 84% in early 2023.

There’s another wrinkle. A significant portion of this trading activity runs through Cayman Islands-domiciled funds. The FEDS Note suggests that Treasury International Capital (TIC) data, the standard measure of foreign holdings of US securities, could be underestimating actual exposures by approximately $1.4 trillion as of the end of 2024.

Beyond the basis trade, the Fed identified other relative-value strategies contributing to hedge fund Treasury exposure. Swap-spread arbitrage accounts for $305 billion, making it the second-largest category but still dwarfed by the basis trade’s dominance.

The data also captured a real-time stress test of sorts. Tariff announcements in April 2025 triggered an estimated $60 billion unwind in swap-spread positions, representing roughly 20% of those holdings. The positions partially recovered afterward, but the episode illustrated how quickly policy surprises can force leveraged Treasury strategies to deleverage.

What this means for investors

Hedge funds’ Treasury holdings now represent approximately 8.5% of all privately held Treasuries, nearly doubling from 4.5% just two years earlier. Basis-trade positions alone account for about 3.5% of privately held Treasuries, a 40% increase from earlier peaks.

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