Form 13H Large Trader Rule: The SEC Filing You Can’t Read

Form 13 filings usually tell you what someone owns. The Form 13H large trader filing tells the SEC how much someone trades, and the public never gets to see it. Under Rule 13h-1, a person whose trading reaches 2 million shares or $20 million in fair market value on a calendar day, or 20 million shares or $200 million in a month, has to identify itself to the SEC and to every broker-dealer it uses.

If you follow insider, congressional and 13F data, this is the missing layer. The SEC’s own 2011 adopting release estimated the rule would affect approximately 400 large traders and 300 registered broker-dealers. Those traders appear in no public feed. Here is how the system works and what it means for the data you can see.

Why the SEC Built a Large Trader System

The trigger was the May 6, 2010 market disruption. When the Commission voted unanimously on July 26, 2011to adopt the rule, Chairman Mary Schapiro said “May 6 dramatically demonstrated the need to enhance the SEC’s ability to quickly and accurately analyze market events.” The SEC said the rule would help it identify high-frequency and other large traders and reconstruct market events, conduct investigations and bring enforcement actions.

The final rule was effective October 3, 2011, adopted under Section 13(h) of the Exchange Act.

Who Is a Large Trader: The 2 Million Share and $20 Million Tests

The statute defines a large trader as a person who, for their own account or an account over which they exercise investment discretion, trades at or above a level the SEC sets (Exchange Act Section 13(h)). The Commission set that level in the rule.

Three details matter. First, hitting either the share or the dollar test is enough. Second, the rule says that “under no circumstances shall a person subtract, offset, or net purchase and sale transactions”, so a trader who buys and sells the same shares counts both sides. Third, a person can’t split accounts to stay under the line. The rule also bars disaggregating accounts to avoid identification.

Certain items don’t count toward the test, including gifts, court-ordered transactions, employer equity awards and issuer buybacks. And a person below the threshold can still register voluntarily by filing Form 13H. The SEC said the level was designed to catch traders responsible for roughly 0.01% of daily volume in NMS securities.

What a Form 13H Large Trader Filing Collects, and the LTID

Form 13His a single form with check boxes for Initial, Annual, Amended, Inactive Status, Termination and Reactivated Status filings. It collects the large trader’s name, identification number, addresses, affiliates and the broker-dealers where it has accounts. The form is filed electronically through EDGAR, and the SEC’s paperwork estimate is about 18 hours per response.

In return, the SEC assigns each large trader a unique identification number, the Large Trader ID or LTID. The trader hands that number to its broker-dealers along with the accounts it covers. From then on, trades in those accounts can be linked to one entity even if they are spread across several firms.

Deadlines: Initial, Annual and Amended Filings, Plus Inactive Status

The initial deadline is “promptly,” not a fixed number of days. Some summaries quote a specific day count, but the rule text does not. A large trader whose trading falls below the activity level for a full calendar year may file for Inactive Status. It stays inactive until its transactions again reach the level.

What Broker-Dealers Must Record and Report

Rule 13h-1(d) puts a recordkeeping duty on the other side. Broker-dealers must keep records for large trader accounts, including the LTID and execution time among other transaction details, and make them available the morning after the transaction date. That timing comes straight from the statute, which requires records available on the morning of the day after the trades.

The data moves through an existing pipe. Broker-dealers report large trader data through the Electronic Blue Sheets system, and per the 2011 release the only new elements were the LTID and the time of execution. A later SEC release confirms broker-dealers must capture and report the execution time and a Commission-issued large trader identifier for large trader trades.

What if a customer never registers? The rule defines an “Unidentified Large Trader.” A broker-dealer that lacks actual knowledge, and keeps reasonable policies to identify such customers, treat them as Unidentified Large Traders and notify them, is deemed not to know.

Why You Won’t Find Form 13H Public

Filers submit Form 13H through EDGAR, but it is not published there. Section 13(h)(7) of the Exchange Act says that “the Commission shall not be compelled to disclose any information required to be kept or reported” under the large trader subsection, and the 2011 release applies the FOIA exemption to Form 13H and the broker-dealer transaction reports. The statute still lets the SEC share the data with Congress, other federal agencies, and courts in government actions.

Form 13H vs Form 13F vs Form 4

The three filings answer different questions. Form 13F covers institutional managers who exercise investment discretion over $100 million or more in Section 13(f) securities and is due within 45 days after each calendar quarter. It is public on EDGAR, subject to confidential treatment requests that we cover in our hidden holdings guide. Form 4 covers company insiders; our Form 4 guide explains it.

The same firm can sit in more than one column, but the filings measure different things: 13H is about trading volume, 13F about quarter-end holdings. For another disclosure regime built around a narrower slice of the market, see Rule 13f-2 and Form SHO.

Compliance in Practice: Exam Findings and Filing Burden

The rule is not dormant. In a December 16, 2020 Risk Alert, SEC examiners reported instances where large traders may not have self-identified or filed their annual Form 13H. They noted that an adviser taking on a new discretionary client could cross the thresholds and become a large trader, and that firms which missed obligations responded by submitting Forms 13H for prior years.

The paperwork is large. In a January 2024 Federal Register notice, the SEC estimated the Rule 13h-1 and Form 13H collection at about 131,415 hours per year: 31,140 for initial filings, 75,300 for updates, 22,200 for broker-dealer reporting and 2,775 for broker-dealer monitoring.

What This Means for Reading Public Signals

Public disclosure covers holdings snapshots, insider trades and congressional reports. The large trader system sits outside that: it is built for regulators who need to reconstruct trading after the fact. For readers, the point is humility. Our post on how the SEC detects insider trading shows how much surveillance data exists that public filings never reveal.

This is education about a disclosure rule. It is not investment advice, and nothing here predicts how any stock will move.