Key takeaways 

• The Securities and Exchange Commission has adopted Rule 13h-1 under the U.S. Securities Exchange Act of 1934 to establish a reporting system for "large traders" to assist the SEC in identifying large market participants and monitoring their trading activity. 
• Under Rule 13h-1, a large trader is required to file Form 13H with the SEC and identify its large trader status to the registered broker-dealers through which it effects trades of National Market System (NMS) securities. Registered broker-dealers must track and monitor the trading accounts of large traders and, upon the SEC's request, provide information on such accounts to the SEC.