Final answer:
Contract performance in futures markets is most likely guaranteed by the exchange clearinghouse, which serves as an intermediary, securing the integrity of the market and reducing the risk of default.
Step-by-step explanation:
In futures markets, contract performance is most likely guaranteed by the exchange clearinghouse. The clearinghouse acts as an intermediary between the buyers and sellers involved in futures contracts, reducing the risk of counterparty default. It ensures the integrity of the market by standing behind the performance of financial obligations specified in the contracts. This system provides a level of security and trust for participants in the exchange rate market, allowing for the orderly processing of transactions and the efficient functioning of the market.