Repo Rate Calculator

A repurchase agreement (repo) is a form of short-term secured borrowing in which one party sells securities to another party with a contractual promise to buy them back at a specified higher price on a future date. The difference between the sale price and the repurchase price represents the repo interest, and the annualized cost of that borrowing is called the repo rate.

Repos are one of the most important instruments in money markets worldwide. Banks, broker-dealers, hedge funds, money market funds, and central banks all rely on the repo market for overnight and short-term financing. On any given day, the U.S. tri-party repo market alone processes trillions of dollars in transactions. The Federal Reserve itself uses repos and reverse repos as primary tools for implementing monetary policy.

From the seller's (borrower's) perspective, a repo is a way to raise short-term cash by temporarily parting with securities while retaining economic ownership. From the buyer's (lender's) perspective, a repo is a low-risk, collateralized investment that earns a modest but reliable return. The collateral — typically government bonds, agency securities, mortgage-backed securities, corporate bonds, or equities — protects the lender in the event the borrower defaults.

The term of a repo can range from overnight (the most common) to several weeks or months. Overnight repos are rolled daily and are extremely sensitive to central bank policy rates. Term repos lock in a rate for a fixed period, offering borrowers more certainty about their funding costs but typically at a small rate premium over overnight repos.

Understanding repo mechanics is essential for fixed-income traders, treasury professionals, and anyone managing a portfolio of securities. This calculator computes the exact cash flows — including the cash received after the haircut, total repo interest, repurchase price, implied annualized rate, and effective borrowing cost — so you can evaluate and compare repo transactions with precision.

The repo rate calculator uses simple interest on an actual/360 day-count basis, which is the market convention for U.S. dollar repo transactions. Every output is derived from four inputs: collateral market value, repo rate, term in days, and haircut percentage.

The haircut reduces the amount of cash the borrower receives relative to the collateral's full market value. This overcollateralization protects the lender against a decline in the collateral's value during the repo term. A 2% haircut on a $10 million Treasury position means the borrower receives $9.8 million in cash, not $10 million.

Once cash received is determined, repo interest accrues on that cash amount using the quoted annualized rate prorated over the actual number of days on a 360-day year basis. The repurchase price equals the original cash received plus the accrued interest — that is the exact amount the borrower must pay at maturity to reclaim the collateral.

The implied annualized rate confirms the round-trip return to the lender expressed as an annual percentage. Because the haircut causes the borrower to pledge more collateral than cash received, the effective borrowing cost (calculated on the full collateral value rather than cash received) is slightly lower than the quoted repo rate.

The haircut is the most important risk-management parameter in a repo transaction. It functions as a margin of safety — by receiving less cash than the collateral is worth, the lender is protected against moderate declines in collateral value before they can be remedied through a margin call or liquidation.

Haircut levels are determined primarily by the volatility and liquidity of the collateral:

• U.S. Treasury Securities (1–2%): The safest and most liquid collateral. Daily price moves are small and the market is deep, so a 1–2% haircut is typically sufficient.
• Agency Securities (2–3%): Slightly more credit risk than Treasuries but still highly liquid. Agency MBS haircuts tend toward the upper end of this range.
• Mortgage-Backed Securities (3–5%): Greater price volatility and more complex cash flows justify a larger cushion.
• Investment-Grade Corporate Bonds (4–6%): Credit risk and lower liquidity require a wider haircut. High-yield corporate bonds would command significantly higher haircuts, often 10–20%.
• Equities (8–15%): The highest intraday price volatility of any commonly used repo collateral category means lenders demand the largest cushion.

During periods of market stress, counterparties often widen haircuts sharply — a dynamic that was vividly illustrated during the 2008 financial crisis when haircuts on structured products surged from low single digits to 30–40%, effectively shutting off funding for entire asset classes. This "haircut spiral" is now widely studied as a key amplifier of financial crises.

The margin ratio (collateral value ÷ cash received) is the inverse complement of the haircut. A 2% haircut yields a margin ratio of roughly 1.020x — for every $1.00 in cash lent, the lender holds $1.02 in collateral. Monitoring the margin ratio over the repo term is critical because falling collateral prices erode the cushion and may trigger margin calls requiring the borrower to post additional collateral.

The repo rate does not exist in isolation — it moves closely with other short-term benchmark rates, particularly the Federal Funds Rate (FFR), the Secured Overnight Financing Rate (SOFR), and the Federal Reserve's own Overnight Reverse Repo (ON RRP) facility rate. Understanding these relationships is essential for anyone financing a securities portfolio.

SOFR is now the primary benchmark rate for U.S. dollar derivatives and many lending products, having replaced LIBOR after 2023. SOFR is calculated as the volume-weighted median of overnight Treasury repo transactions, which means it is directly tied to the repo market. When repo rates rise, SOFR rises, and floating-rate instruments indexed to SOFR become more expensive to service.

The Fed's ON RRP facility sets an effective floor under money market rates: eligible counterparties can always invest overnight at the ON RRP rate, so repo rates cannot sustainably fall much below that level without an enormous migration of cash to the Fed. Similarly, the interest on reserve balances (IORB) paid by the Fed to banks caps the rate at which banks will borrow in the repo market.

For term repos beyond overnight, a small term premium typically applies. Borrowers accept a slightly higher rate in exchange for locked-in funding certainty. This calculator estimates the daily interest cost (repo interest ÷ days) to help you compare term and overnight alternatives on an apples-to-apples basis.

Central banks in many countries use repo operations as their main tool for injecting or draining liquidity. When a central bank conducts an open market purchase, it buys securities from banks under a repo agreement, injecting cash into the system. A repo operation in central-bank parlance typically refers to the central bank lending cash against collateral — the mirror image of a dealer repo.

A repo rate calculator serves multiple real-world purposes across trading desks, treasury functions, and portfolio management teams.

Financing cost analysis: Fixed-income traders who purchase bonds on leverage must understand the all-in cost of carry. If a 10-year Treasury yields 4.50% and the overnight repo rate is 5.30%, the trader is in a negative carry position — they pay more to finance the position than the bond earns. The calculator makes this arithmetic explicit by showing exact interest costs for any combination of rate, term, and collateral.

Collateral optimization: Portfolio managers with multiple eligible collateral types can use the calculator to compare the effective borrowing cost under different haircut scenarios. Substituting higher-haircut collateral (say, MBS at 4%) for lower-haircut collateral (Treasuries at 2%) reduces cash received and implicitly raises the effective borrowing cost even if the quoted repo rate is identical.

Trade settlement and reconciliation: Back-office and middle-office teams use repo calculators to verify the repurchase price on repo confirmations. Even small discrepancies in day-count or haircut assumptions can produce meaningful differences in the repurchase price on large notional transactions.

Risk management: The margin ratio output helps risk managers determine how much collateral price movement can be absorbed before a margin call is triggered. A 2% haircut on a Treasury repo means the collateral can fall roughly 2% before the lender's position becomes uncollateralized — understanding this threshold is central to repo risk management frameworks.