The process used by market participants, prior to settlement, to ensure they agree on the terms of the transaction. This is usually performed by a counterparty matching the transaction confirmation sent to a counterparty with the confirmation received from that counterparty. Settlement instructions that have been successfully matched between counterparties are referred to as matched settlement instructions. In some securities settlement systems, penalties may apply to participants that unilaterally revoke matched settlement instructions. In other systems, unilateral revocation of matched settlement instructions may not be possible.