Under the system of a basket of deliverable bonds, all government bonds with a certain remaining maturity can participate in delivery. Due to different yields and remaining maturities, the prices of deliverable government bonds are also different. Even if the conversion coefficient is used for conversion, there are still subtle differences between various deliverable national bonds. In general, because the seller has the option to deliver bonds, the seller of the contract will choose the bonds that are most beneficial to him and usually have the lowest delivery cost, and the corresponding bonds are the cheapest deliverable bonds. Theoretically, by comparing the implied repo rates of different bonds, the cheapest deliverable bonds can generally be found.

According to overseas practical experience, under certain preconditions, the cheapest deliverable bonds can be roughly found by comparing duration and yield:

(1) Duration: For the treasury bonds whose yield is lower than that of coupon rate, the treasury bonds with the shortest duration are most likely to be the cheapest deliverable bonds. For the bonds with higher yield than coupon rate's bond futures contract, the bonds with the longest duration are probably the cheapest deliverable bonds.

(2) Yield: For the government bonds with the same maturity, the government bonds with the highest yield are most likely to be the cheapest deliverable bonds.