The SEC adopted new Rule 13h-1 and Form 13H under the Securities Exchange Act of 1934 earlier this year, to assist the Commission in both identifying, and obtaining trading information on, market participants that conduct a substantial amount of trading activity, as measured by volume or market value, in the U.S. securities markets.  The rule became effective 10/3/11. On Tuesday, 12/27, the SEC released Form 13H in pdf format.  The form is captioned: "Information Required of Large Traders Pursuant To Section 13(h) of the Securities Exchange Act of 1934 and Rules Thereunder."  A link to the form is provided, below. The SEC expects the large trader reporting requirements, among other things, to support its investigative and enforcement activities - e.g., to reconstruct trading activity following periods of unusual market volatility, and to analyze significant market events for regulatory purposes - such as following the Flash Crash of 5/6/10. “Large Trader” Defined. A person whose transactions in NMS securities equal or exceed 2 million shares or $20mn during any calendar day, or 20 million shares or $200mn during any calendar month.  That person is required to identify itself to the SEC and make certain disclosures on Form 13H.  Upon receipt of Form 13H, the SEC will assign to each large trader an ID# that will uniquely and uniformly identify the trader, which the large trader must then provide to its registered broker-dealers. A Broker-Dealer's Obligations. After receiving the ID# from a large trader, a broker-dealer will be required to maintain records of 2 additional data elements in connection with transactions effected through accounts of such large traders:  (i) the large trader ID#;  (ii) time of execution for transactions in the account. The B/D also will be required to report large trader transaction information to the SEC upon request through the Electronic Blue Sheets systems currently used by broker-dealers for reporting trade information.  Finally, certain B/D's will be required to perform limited monitoring of their customers’ accounts for activity that may trigger the large trader ID requirements of Rule 13h-1.     For further details, go to:  [SEC Form 13H, Large Trader Registration] and    [SEC Final Rule Rel. 34-64976].