Repo

Also known as: Repurchase agreement, Reverse repo

Sell a bond today, buy it back tomorrow: the secured loan that finances the entire bond market.

4 min read · 650 words · Updated

1 · SnapshotThe one idea to remember
Key intuition: repo converts securities into cash and back, overnight, at scale. It is the financial system's bloodstream — invisible when healthy, unmistakable when not.
2 · BeginnerWhat is it, really?

A repurchase agreement is a loan dressed as two trades: you sell a security today and commit to buy it back tomorrow (or next week) at a slightly higher price. The price difference is interest — the repo rate — and the security is the lender's collateral throughout.

Repo is how the bond world breathes. Dealers finance their inventories with it; hedge funds lever positions through it; money funds lend cash into it; central banks implement policy with it. Almost every leveraged bond position in the world is funded here — it is arguably the most systemically important market almost nobody outside finance has heard of.

Because the loan is over-collateralised (you lend 98 against a bond worth 100 — the gap is the haircut) and usually overnight, repo is about as safe as lending gets. Which is precisely why, when repo does seize up, everything else does too.

A loan that is legally a sale
Cash borrowerowns bondsCash lenderhas cash1The bonds, sold outright2Cash, less the haircut3Margin, as prices move4The same bonds, back5Cash plus the repo rate6The lender simply sells

a paymentsomething deliveredonly if a condition is met

Calling it a loan explains the economics. Calling it a sale explains what happens if the other side fails, which is the reason it is written this way.

The opening leg, same day

  1. Cash borrower → Cash lender Legal title passes. This is not a pledge, and that distinction is the whole point of the documentation.
  2. Cash lender → Cash borrower Less than the bonds are worth. The gap is the lender's cushion against the price falling before it can sell.

legally a sale and a repurchase, not a secured loan

Every day, if it runs longer

  1. Cash borrower → Cash lender The collateral is revalued daily and topped up. A haircut that was comfortable yesterday may not be today.

The closing leg

  1. Cash lender → Cash borrower Repurchased at the agreed price.
  2. Cash borrower → Cash lender The difference between the two prices is the interest. Nothing was ever called a loan.

If the borrower fails

  1. Cash lender → Cash borrower It already owns the bonds and does not have to wait for an insolvency process. That is what the sale structure bought.
Asset class
Money markets
Instrument type
Collateralised loan (sale + repurchase)
Traded
OTC + cleared (FICC, Eurex)
Typical users
Dealers, hedge funds, money funds, central banks

Which risks decide the outcome

Not how risky this is, and not a rating — there is deliberately no total. It says which of five failure modes drives what happens here, in the same order on all 129 products so they can be compared. This publication's own reading; see the notice below.

  • Marketmatters
  • Creditmatters
  • Liquiditybarely applies
  • Fundingdecides it
  • Operationaldecides it

What decides it here. Collateralised, marked daily, and legally a sale — so credit is small. Funding is the whole risk: a balance sheet financed overnight is re-underwritten every morning by people free to decline.

What the five mean, and which one decides where →

3 · IntermediateHow it works in practice

Mechanics and jargon

  • Repo / reverse repo: same trade from the two sides — cash borrower vs. cash lender.
  • GC (general collateral): any acceptable government bond will do; the GC rate is effectively a secured policy-rate satellite (SOFR is computed from US repo).
  • Specials: when everyone needs one particular bond (to deliver into shorts or futures), its repo rate falls below GC — owners of that bond can borrow cash abnormally cheaply. Specialness = a lending fee on a hot security.
  • Term, open, tri-party: durations beyond overnight; tri-party agents (BNY) handle collateral operationally.

Haircuts and leverage

A 2% haircut means 50x potential leverage on government bonds — the fuel of basis trades. Haircut spirals (collateral falls → haircuts rise → forced sales → collateral falls) are the modern bank-run mechanism: Bear Stearns and Lehman died in the repo market before they died anywhere else.

Policy plumbing

Central banks steer short rates through repo: the Fed's RRP facility (floor) and Standing Repo Facility (ceiling) corral the corridor; September 2019's repo spike (rates briefly 10%) forced the Fed back into daily operations — a masterclass in why reserves scarcity matters.

Worked example: a fund buys $100M of Treasuries, repos them at a 2% haircut: posts $2M of its own cash, borrows $98M at the repo rate. If the bond yields 4.5% and repo costs 4.3%, the 20bp carry on $100M is levered onto $2M of capital → ~10% return — plus full exposure to any price move, both ways.
4 · AdvancedPricing & valuation

Pricing relationships

Repo is the financing leg inside nearly every fixed-income arbitrage:

$$ \text{Forward bond price} = (S + AI_0)\,(1 + r_{repo}\tau) - c\!\cdot\!\tau - AI_T $$
What the symbols mean
  • Sthe price of the underlying today
  • rthe interest rate, per year
  • tautime remaining, in years
  • cthe coupon rate
  • Tmaturity, in years

Specialness enters as a dividend-like yield: a special bond's forward is higher (cheaper to hold via repo), and futures cheapest-to-deliver analysis, bond rich/cheap and swap spreads all run on repo assumptions. The implied repo rate backed out of futures vs. cash is the basis trader's core number.

Specialness economics

Auction cycles, short bases, and collateral scarcity set specialness; the fails penalty (Treasury: ~3% floor) caps how special a bond can trade. Persistent specialness feeds into on-the-run premia — a liquidity/collateral value embedded in benchmark bond prices.

Systemic mechanics

  • Rehypothecation chains: the same collateral secures multiple loans in sequence — efficiency and fragility simultaneously; collateral velocity is a monitored aggregate.
  • Cleared vs. bilateral: post-2008 reforms push repo into CCPs (US Treasury clearing mandate phasing in) — netting shrinks balance sheets but concentrates the CCP.
  • NBFI leverage: hedge-fund Treasury basis books financed at minimal haircuts are the current policy obsession (2020's dash-for-cash unwound exactly this).
$$ \text{SOFR} = \text{volume-weighted median of cleared+tri-party GC repo} $$

The formulas above are standard textbook formulations, simplified for teaching. They explain the mechanism — they are not a valuation tool, and they will not reproduce a dealer’s price.

5 · Desk notesHow practitioners think about it
Practitioner note: to understand any leveraged fixed-income strategy, find its repo: the rate, the haircut, the roll risk. That's where the strategy's true capacity — and its death — are written.

Now say it back

Close the page and give Repo in four sentences. It takes a minute and it is the only way to find out whether reading it was enough.

  1. Who wants what — two parties wanted opposite things badly enough to write it down.
  2. What the contract obliges, and when — not the payoff; the obligation.
  3. Where the money comes from — name the source, or you have described a hope.
  4. What makes it lose — the ordinary way, not the dramatic one.

Do it with a clock → · why these four

Put Repo beside any other instrument →

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