Basis Trade¶
OVERVIEW¶
A basis trade is a relative-value arbitrage strategy that exploits the basis — the small price gap between a cash bond and its corresponding futures contract. In its most common institutional form, a hedge fund buys a cash Treasury note, simultaneously sells the equivalent Treasury futures contract, and finances the cash position in the overnight repo market using 20x to 50x leverage to convert a fractional-cent spread into a meaningful return on capital.
The basis converges to zero at futures expiration by construction. The risk is not in the spread itself — it is in the leverage and financing required to hold the position open until convergence.
Note
The basis trade is a pure institutional strategy. It requires prime-broker repo access and is not available through a retail brokerage account.
HOW THE BASIS IS CALCULATED¶
| Formula | Expression |
|---|---|
| Gross Basis | Cash Bond Price − (Futures Price × Conversion Factor) |
| Net Basis | Gross Basis − Carry |
| Carry | Coupon Income Earned − Repo Financing Cost (over the holding period) |
The conversion factor normalizes a specific deliverable bond's price to the futures contract's notional 6% coupon standard.
When net basis is positive, the cash-futures spread offers more return than the cost of holding and financing the position — the setup a basis trader is hunting for.
WORKED EXAMPLE¶
A 10-year Treasury note trades at $99.50 per $100 face. The cheapest-to-deliver futures contract trades at $118.00 with a conversion factor of 0.8420.
| Step | Calculation | Result |
|---|---|---|
| Futures-adjusted price | $118.00 × 0.8420 | $99.356 |
| Gross basis | $99.50 − $99.356 | $0.144 per $100 face |
| Notional position | $500 million face value | — |
| Gross basis dollar value | $500M × 0.00144 | $720,000 |
| Leverage applied | ~20:1 (~$25M margin capital) | — |
Tip
At 20:1 leverage, a gross basis of 14.4 basis points on a $500 million position converts into a return in the high single digits on capital actually deployed, before financing costs and hedging expense.
WHEN TO USE IT¶
Basis trades are used by relative-value macro hedge funds operating at institutional scale. The strategy serves two functions:
- Earns a leveraged repo-financed carry spread on the cash-futures gap
- Provides meaningful daily liquidity connecting the cash and futures Treasury markets
Similar basis logic applies to:
| Instrument Pair | Basis Relationship |
|---|---|
| Treasury note vs. Treasury futures | Cash price vs. futures-adjusted price |
| Index futures vs. underlying basket | Futures premium or discount to index level |
| ETF share price vs. net asset value | Market price vs. NAV per share |
LIMITATIONS AND COMMON MISCONCEPTIONS¶
Note
The basis trade is not risk-free arbitrage despite how it is often described. The risk is funding risk, not price risk.
| Risk Factor | Description |
|---|---|
| Repo rate spike | Rising overnight rates increase financing costs, compressing or eliminating the spread |
| Haircut widening | Prime brokers requiring larger collateral buffers reduce effective leverage |
| Margin call before expiration | Forced unwind at a loss before the basis converges |
| Systemic amplification | Rapid unwinds across many funds can destabilize the broader Treasury market |
The March 2020 repo funding freeze forced rapid basis-trade unwinds that amplified the Treasury market sell-off and required direct Federal Reserve intervention. The Fed and the Office of Financial Research have repeatedly flagged record leveraged-fund short positioning in Treasury futures — the basis trade's short leg — as a standing financial-stability risk.
A position that converges to zero at expiration on a spreadsheet can still produce large realized losses if forced to close before expiration.