Dont Know (DK)
Definition - What does Dont Know (DK) mean?
Don't Know (DK) is a term used to describe a dealer’s response to a confirmation for a trade they "don’t know" executing.
Testopedia explains Dont Know (DK)
A don't know or a DK is an unconfirmed or open trade. It is a trade that one party reports and the terms of the trade are not recognized by the confirming party. Many DKs are the result of a discrepancy in price or the number of shares.The DK may also be the result of an input error or typo and can be easily resolved.