Cheapest to Deliver (CTD)

What Is Cheapest to Deliver (CTD)?

The cheapest-to-deliver (CTD) bond is the specific Treasury security that the short holder of a futures contract will elect to deliver to satisfy the contract at expiration. Because Treasury futures contracts (10-year, 30-year, ultra bonds, etc.) allow delivery of any bond from a defined deliverable basket — bonds meeting certain maturity and coupon criteria — the short side has an embedded delivery option: they choose whichever eligible bond minimizes their delivery cost relative to the futures price, adjusted by the conversion factor (CF) assigned by the CME to each deliverable bond.

The net cost of delivering a bond is:

Delivery Cost = Invoice Price Received − (Spot Price of Bond + Accrued Interest)

where Invoice Price = Futures Price × Conversion Factor + Accrued Interest. The bond with the lowest delivery cost — or equivalently, the highest implied repo rate — is the CTD.

Why It Matters for Traders

CTD dynamics are foundational to Treasury Basis Trade positioning, a strategy involving simultaneously buying cash Treasuries and selling futures (or vice versa) to capture the net basis. Hedge funds and primary dealers run basis books sized in hundreds of billions of dollars. When the CTD switches — meaning a different bond in the deliverable basket becomes cheapest — the entire basis trade can reprice abruptly, forcing rapid rehedging.

CTD identity is also critical for interpreting Duration and DV01 of futures contracts. If market participants assume the wrong CTD bond, their hedge ratios will be systematically off, creating basis risk. During periods of elevated repo market stress (visible in the Repo Rate), CTD bonds can go 'on special' in the repo market, altering their effective carry and shifting which bond is cheapest.

How to Read and Interpret It

Key analytical checkpoints:

• Conversion factor vs. duration: CTD tends to be the bond in the basket whose duration most closely matches the futures contract's notional 6% coupon standard bond, but in low-rate environments, high-duration bonds dominate; in rising-rate environments, low-duration bonds become CTD.
• CTD switches near yield inflection points: When the yield curve moves through ~6% (the CME notional coupon), CTD switches occur most aggressively, causing sharp basis repricing.
• Gross basis vs. net basis: Gross basis (Cash Price − Futures Price × CF) includes carry; net basis (gross basis minus carry) isolates the delivery option's value. A widening net basis signals the delivery option is gaining value — typically in volatile, illiquid conditions.
• Implied repo rate: If the implied repo rate of a bond exceeds the general collateral Repo Rate, that bond is likely CTD; a compressed implied repo signals it is being displaced.

Historical Context

During the March 2020 Treasury market dislocation, extreme volatility in yields caused multiple CTD switches across the Treasury futures curve within days. Basis positions that had been financed at tight repo spreads suddenly faced CTD bonds trading at punishing special rates in the repo market — in some cases, specific Treasury issues traded 200–300 basis points below general collateral. The resulting forced unwinds by levered basis traders amplified Treasury market illiquidity, prompting the Federal Reserve to launch emergency asset purchases. This episode became the central case study motivating regulatory scrutiny of the Treasury Futures Basis Trade.

Limitations and Caveats

CTD analysis assumes clean repo financing and predictable delivery mechanics — both of which break down in stress periods. The delivery option value (embedded in the short's right to deliver any basket bond) is theoretically a stochastic option, but most practitioners use simplified static models. Additionally, CTD analysis is strictly relevant at or near futures expiration; in the interim, basis dynamics can diverge meaningfully from delivery-day economics. The framework also does not easily accommodate partial deliverability complications arising from foreign holdings of specific Treasury issues.

What to Watch

• CME deliverable basket compositions and conversion factors at each quarterly roll.
• Repo specialness screens for current deliverable basket bonds — specialty premiums signal CTD pressure.
• CFTC COT Report for positioning in Treasury futures as a proxy for aggregate basis trade size.
• Federal Reserve SOMA holdings — large Fed ownership of specific issues can create artificial scarcity in the deliverable basket.