Implied Repo Rate¶
The implied repo rate is the annualized return a trader earns by buying a cash Treasury security and simultaneously selling a futures contract on that security, holding both until delivery. It represents the financing rate implied by the price difference between the cash bond and the futures contract. Basis traders use it to identify arbitrage opportunities between the cash and futures markets.
HOW IT WORKS¶
The implied repo rate is derived from the cash-futures basis using the following formula:
Implied Repo Rate = ((Futures Price × Conversion Factor − Cash Price) / Cash Price) × (360 / Days to Delivery)
The conversion factor adjusts the futures price to reflect the deliverable bond's specific coupon and maturity relative to the futures contract's notional terms. When the implied repo rate exceeds the prevailing repo rate, a trader can buy the cash bond, sell the futures contract, and finance the position in the repo market to lock in the spread. When it falls below the actual repo rate, the reverse trade applies. The bond that maximizes the implied repo rate across all eligible deliverables is the cheapest-to-deliver (CTD).
Note that the implied repo rate assumes the position is held to delivery and ignores transaction costs, bid-ask spreads, and margin requirements. The actual repo rate can shift during the holding period, affecting the realized return.
IN TAPEBOARD¶
Tapeboard displays the implied repo rate alongside the gross and net basis for each deliverable bond in the futures contract chain. Traders can rank deliverables by implied repo rate to identify the current CTD and monitor how that designation shifts as rates and prices move. Alerts can be configured to flag when the implied repo rate on a given bond crosses the prevailing repo rate, signaling a potential basis trade entry or exit.