Repo is how Wall Street borrows cash overnight against Treasuries. Here is how a repo trade works, who lends and borrows, what broke in September 2019, and what the 2026–27 clearing deadlines change.
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The repo market is where institutions borrow cash for a day or a few weeks by pledging securities, mostly US Treasuries. In a repurchase agreement the borrower sells the securities and agrees to repurchase them at a set price on a set date; the price difference is the interest. To the lender of cash the same trade is a reverse repo. Because the loan is backed by collateral and is very short, it is cheap: on October 22, 2026, overnight Treasury repo cost 3.90%, the Secured Overnight Financing Rate published by the New York Fed.
Scope. US dollar repo, as of October 26, 2026: how a trade works, who uses it, the Fed’s backstops and the Treasury clearing rule. It does not cover securities lending of stocks, European repo or tokenized repo. It is education, not advice.
Worked example (illustrative). A dealer needs $100 million overnight to finance Treasuries it bought at an auction. A money market fund lends the cash; the dealer delivers $102 million of Treasuries. The $2 million gap corresponds to a 1.96% haircut ($2 million divided by $102 million), the lender’s cushion if the dealer fails and the bonds must be sold. Repo interest uses an actual/360 day count, so one night at 3.90% costs $100,000,000 × 0.039 × 1/360 = $10,833.33. Next morning the dealer pays back $100,010,833.33 and gets its bonds back, or both sides roll the trade for another night.
Two features explain both the usefulness and the danger. The loan is short, so a borrower funding long-term bonds must find cash again every day. And the haircut and the collateral’s value can change overnight: if lenders ask for a 5% haircut instead of 1.96%, the same $102 million of bonds supports only about $97 million of cash, and the borrower must find the rest or sell. That is how repo carries stress from one firm to many, as described in how financial crises spread.
The Office of Financial Research put US repo at about $12.6 trillion in average daily exposures in Q3 2025, $700 billion more than earlier estimates, once it began collecting data on the uncleared bilateral segment (OFR, December 2025). In the second half of 2025, home loan banks and other government-sponsored enterprises, money funds and other investment funds lent nearly $3.5 trillion on net, and hedge funds borrowed more than $1.8 trillion on net (OFR Brief 26-03).
The fed funds market, which the Fed targets, is small by comparison because banks with ample reserves rarely need to borrow them. Daily volume on October 22, 2026:
| Repo segment (Q3 2025 daily average) | Size | How it works |
|---|---|---|
| Centrally cleared (FICC) | $4.4T | A clearinghouse stands between both sides |
| Tri-party, not centrally cleared | $3.1T | A custodian bank holds and values the collateral |
| Bilateral, not centrally cleared | $5.0T | Two firms trade and settle directly |
| Total | $12.6T | Daily exposures, not annual volume; segments are rounded |
Overnight repo rates spiked because two routine cash drains hit when reserves were already low. On September 16, 2019 corporate tax payments moved from bank and money fund accounts to the Treasury’s account at the Fed, and $54 billion of Treasury coupon debt settled. Reserves fell by about $120 billion over two business days to roughly $1.34 trillion, the lowest since 2012. The benchmark repo rate went from 2.43% on September 16 to 5.25% on September 17, and the fed funds rate printed above its target range (FEDS Notes; daily rates via FRED).
The New York Fed offered up to $75 billion of overnight repo on the morning of September 17, adding $53 billion of reserves that day, and the rate was back to 2.55% on September 18. On October 11, 2019 the Fed announced Treasury bill purchases of about $60 billion a month to rebuild reserves. Lenders did not step in despite the high rates, which is the lesson the Fed drew: in a squeeze, cash holders hold on to cash.
They are the floor and the ceiling of overnight rates. Through the overnight reverse repo facility, money funds and other eligible firms lend cash to the Fed at 3.75%, up to $160 billion each per day. Through the standing repo facility, created on July 28, 2021 with a $500 billion maximum operation size, eligible dealers and banks borrow cash from the Fed at 4.00% against Treasury and agency collateral ( implementation notes of Sept 16 and Oct 28, 2026). Both move with the target range, 3.75%–4.00% (raised on September 16, 2026, held on October 28).
| Date | Fed reverse repo use | What it signals |
|---|---|---|
| Dec 30, 2022 | $2,553.7B (peak) | Money funds had more cash than private repo and bills could absorb |
| Oct 23, 2026 | $0.2B | Funds have moved that cash into bills and private repo |
Source: New York Fed via FRED (RRPONTSYD). A near-empty facility is not a stress signal by itself; it means the spare cash cushion that once absorbed swings is gone, so swings now show up in repo rates and in standing repo use instead. How the Fed sets these rates is covered in how the Fed sets interest rates.
It is an SEC rule, adopted in December 2023, that requires members of a Treasury clearinghouse to send eligible secondary-market Treasury trades to central clearing. After a one-year extension on February 25, 2025, the deadlines are December 31, 2026 for eligible cash trades and June 30, 2027 for eligible repo (SEC). FICC has been the main clearinghouse; on December 1, 2025 the SEC also approved CME Securities Clearing to clear Treasuries (SEC statement).
A central counterparty nets trades and collects margin, so one firm’s default is less likely to spill to its trading partners. The cost is margin and new fees, which may change how cheaply hedge funds and dealers can borrow. The Office of Financial Research estimates the repo deadline could add slightly more than $500 billion a day to the volume behind the benchmark repo rate while moving the rate by about 0.01 point (OFR, October 20, 2026). Those deadlines have already moved once and could move again.
Repo matters to most investors indirectly. Money market funds that hold household cash are its biggest lenders, Treasury prices depend on dealers being able to finance inventory, and repo rates are the basis for reference rates used to price consumer and business loans. The US Treasury market itself is covered in how the bond market works, and money funds as a place for cash in where to park large cash.
When repo headlines are wrong. Many “repo stress” stories describe predictable pressure on tax dates, Treasury settlement days and quarter-ends, when rates rise for a day and fall back. A one-day move above the Fed’s range is a plumbing event, not a forecast of a market fall; September 2019 calmed within a day of Fed operations. The repo episodes that mattered most, 2008 and March 2020, were driven by losses or a scramble for cash elsewhere that reached repo through collateral and haircuts.
Limitations. Segment sizes are exposures averaged over a quarter and are revised as reporting improves; the uncleared bilateral segment has been measured only since 2025. Daily rates and volumes are from the New York Fed’s published benchmarks, which cover overnight Treasury repo, not all repo. The wider picture is in how the financial system works.
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A repo is a short-term loan of cash secured by securities, usually Treasuries. The borrower sells the securities and agrees to buy them back, often the next day, at a slightly higher price that works as interest.
They are two sides of one trade. The cash borrower does a repo; the cash lender, who takes the securities as collateral, does a reverse repo. When the Fed runs a reverse repo facility, the Fed is the borrower and money funds are the lenders.
About $12.6 trillion in average daily exposures in Q3 2025, according to the Office of Financial Research. Overnight Treasury repo alone traded $2.95 trillion on October 22, 2026.
The haircut is the gap between the value of the collateral and the cash lent. With a haircut of about 1.96%, $102 million of Treasuries supports $100 million of cash; if haircuts rise, the borrower gets less cash for the same bonds.
A corporate tax date and $54 billion of Treasury settlements drained about $120 billion of reserves over two business days, leaving them at about $1.34 trillion. The benchmark repo rate rose from 2.43% to 5.25% on September 17, 2019, and fell back after Fed repo operations.
A daily Fed facility, created on July 28, 2021, that lends cash overnight to eligible dealers and banks against Treasury and agency collateral. Its rate, 4.00% since September 17, 2026 (unchanged on October 28), caps overnight secured rates.
Under the SEC rule as extended on February 25, 2025, eligible Treasury cash trades must be cleared by December 31, 2026 and eligible repo by June 30, 2027.
Not by itself. Many spikes are tied to tax dates, settlements and quarter-ends and fade within days. Repo becomes dangerous when losses or a scramble for cash elsewhere cause lenders to pull back or raise haircuts, as in 2008 and March 2020.
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Educational content, not investment advice. Examples are illustrative; past performance does not guarantee future results.