Yield Curve in Money Market

The yield curve in the money market is the term structure of interest rates for instruments maturing in one day to one year—T-bills, commercial paper, banker’s acceptances, and certificates of deposit. Like the longer-term yield curve, it shows how rates vary across maturity, but it operates at much shorter horizons where overnight Fed funds and LIBOR dynamics dominate.

The short-end curve: overnight to 12 months

The money market curve begins at the overnight rate—the Federal Funds Rate in the US or SONIA in the UK. The Fed does not directly control overnight rates but rather sets a target range and supplies or drains reserves via open market operations to steer actual rates within that band.

From there, the curve extends to 1-week, 1-month, 3-month, 6-month, and 12-month maturities. The most-traded instruments are T-bills (especially 3-month and 6-month), commercial paper (mostly 30 and 90 days), and LIBOR or SOFR swap rates. Each has its own supply/demand, credit spread, and trading volumes, creating a distinct maturity structure.

Drivers: Fed policy, credit conditions, and supply

The money market curve is primarily driven by expectations of Federal Reserve policy. If markets expect the Fed to hold rates steady for 12 months, the curve is flat. If markets expect cuts, the longer-dated rates fall below overnight, creating an inverted curve. If the Fed is hiking, the curve often slopes upward as traders expect future rates to be higher than current.

Credit risk is the second major driver. During financial stress—bank failures, corporate downgrades, or systemic risk concerns—credit spreads on commercial paper, banker’s acceptances, and private CDs widen sharply. The 2008 financial crisis saw commercial paper spreads explode as issuers could not roll maturing paper; the Federal Reserve had to backstop the market with the Commercial Paper Funding Facility.

Supply-demand imbalances also matter. If the U.S. Treasury is issuing a large volume of 3-month T-bills to fund the deficit, yields on 3-month bills may rise relative to other maturities. Similarly, if corporations are issuing vast volumes of commercial paper to fund short-term working capital, the CP curve may steepen at the short end.

Term premium and liquidity

The money market exhibits a term premium—longer maturities trade at higher yields than overnight rates, even when Fed policy is expected to be unchanged. This premium compensates for rollover risk (reinvestment risk) and illiquidity. A 3-month T-bill yields more than overnight T-bills because you are locking in capital for longer.

However, the term premium is sometimes negative. In 2018–2019 and again in 2024, when repo rates spiked and money market funding tightened, 3-month and 6-month rates briefly exceeded 1-year rates. This reflects acute funding stress and the Fed’s need to inject liquidity.

Spreads within the money market

Beyond the overnight-to-12-month curve, credit spreads separate different instruments. Treasury bills are risk-free (backed by the U.S. government). Commercial paper from a AAA-rated financial company might trade 25 basis points above T-bills of the same maturity. Paper from a BBB-rated industrial company might trade 50+ basis points wider.

LIBOR (the interbank borrowing rate) and its replacement SOFR (Secured Overnight Financing Rate) are closely tied to the Fed Funds rate but include a credit spread reflecting interbank lending risk. Historically, LIBOR was 10–50 basis points above overnight Fed Funds, depending on credit stress.

During the 2008 crisis, this spread exploded to 300+ basis points as banks feared counterparty defaults. It narrowed back to 10–20 basis points as credit improved. This spread is a barometer of systemic credit risk.

Practical instruments and uses

Treasury Bills dominate. They are issued weekly by the U.S. Treasury in 4-week, 13-week (3-month), 26-week (6-month), and 52-week (1-year) maturities. The 3-month T-bill is considered the risk-free rate benchmark for the money market.

Commercial Paper is issued by corporations and financial institutions to fund short-term working capital. Maturities range from 1 to 270 days (beyond 270 days requires SEC registration). The rate depends on the issuer’s credit rating and the Federal Funds Rate.

Certificates of Deposit are bank deposits; rates depend on the bank’s creditworthiness and the deposit insurance guarantee. FDIC insurance protects up to $250,000 per depositor, so uninsured portions carry a credit spread.

Money Market Funds are mutual funds that hold T-bills, commercial paper, and CDs, offering investors a liquid place to park cash. They seek to maintain a stable $1 share price while earning the average money market yield.

Relation to the longer-term curve

The money market curve is the left edge of the full yield curve. It incorporates the current Federal Funds Rate and near-term policy expectations. When the Fed is hiking, the money market curve often inverts before the longer curve—3-month rates fall relative to overnight as traders price in future cuts.

During quantitative easing periods, when the Fed holds overnight rates near zero and buys longer-dated bonds, the money market curve remains flat (near 0%) while longer maturities rise, creating a steep overall curve.

Measurement and volatility

Money market volatility is measured in basis points, and moves are typically small—5–10 basis points per day in calm periods. During crises (the 2008 financial crisis, the 2020 March volatility, the 2023 bank-failure panic), daily moves of 50–100 basis points are common.

The Fed Funds Futures market, trading on the CME, allows traders to lock in expected Fed Funds rates for future months. The December Fed Funds Future contract reflects market expectations for the average Fed Funds Rate over December; by comparing this to the current overnight rate, traders infer market views on rate changes.