What is the largest USD clearing?

Can you elaborate on the term "largest USD clearing"? Are you referring to the largest amount of US dollars that have been cleared or settled in a single transaction, or perhaps the largest financial institution or platform that handles the majority of USD clearing? Additionally, is there a specific context or industry you are referring to, such as the foreign exchange market, securities trading, or cross-border payments? Clarifying these points would help me provide a more accurate and informative answer to your question.