How filer groups are built

Method §4.5. Version 1.1, 2026-10-05.

Which CIKs count as one manager, with the evidence for every link.

Worked examples describe the reference filings used to check this method. Counts are tied to the dated reference data and may differ from current site coverage. Example pages become available as their filings are imported.

The rule

A filer group is a set of CIKs, and of named persons without a CIK, that the site treats as one manager. Links come from five rules, and each one is shown on the group page with the filing it was read from:

• address: two 13F filers active in the last four quarters with the same distinctive name prefix and the same building (street and zip from the cover page).
• notice: a 13F-NT or combination report and a manager that reports for it, when the names agree, or when a notice names that manager alone and the manager is not a platform that files for many unrelated advisers.
• included: a 13F and an other included manager it lists, when the names agree.
• 13dg: the filer and each reporting person of a 13D or 13G.
• form345: the reporting owners of a Form 3, 4 or 5.

The guards are conservative:

• Second link of another rule. A joint 13D, 13G or Form 3, 4 or 5 between two entities under different names counts only with a second link between the same two from another rule (a notice, an address, a 13D beside a Form 4). Co-investors file jointly without being one manager.
• Holder guard. A link whose names differ never joins two parts that both hold 13F positions in their latest quarter, unless they already share a name prefix or a building.
• Person bridge. A named person without a CIK joins one part and never bridges two.
• Joint-link cap. A 13dg or form345 link never grows a part past 60 members.
• Stated names. A manager named in a 13F list must carry the name of the CIK its file number resolves to.
• Hand entries can add, remove or keep apart members, each with its reason.

Validity quarters. Each member counts only inside the quarters its evidence covers: a notice or included link from the first quarter a loaded 13F shows it to the last, a joint filing from its quarter on, an address or hand entry without bound unless one is set. So a firm acquired in 2025 is not summed into its new parent for 2024, and the quarter a member joins reads as a membership change, not as a buy.

How often

In the data loaded on 2026-10-05: 1,340 groups (10 by hand), 5,585 members, 903 groups with a 13F filer and 693 with several. 3,407 members carry a first valid quarter and 8 a last one. Links counted: address 720, notice 1,896, included 1,170, 13dg 2,371, form345 5,129. The second-link guard removed 2,019 joint links, the holder guard 15, the person-bridge rule 3. A random draw of 30 automatic groups checked by hand found 29 right and one unsure.

Worked example

The Pale Fire Capital group has five members: Pale Fire Capital SE (CIK 1922318, the 13F filer), Pale Fire Capital investicni spolecnost a.s. and the founders Dušan Šenkypl and Jan Barta (each filing a 13F-NT that names Pale Fire Capital SE), and Pale Fire Capital SICAV a.s., which holds the shares directly and appears as a reporting person on the 13D, 13G and Form 4 filings. Jan Barta's notice for Q2 2026 (0000921895-26-002115) names Pale Fire Capital SE as the only manager reporting for him, which is the notice link. That is why the LSPD 13G (0000921895-26-002694), filed by Pale Fire Capital SE with five reporting persons, lands on the same timeline as the SE's 13F.

On a stock page, holders are collapsed by group: Vanguard's subsidiaries that each file a 13F count as one manager, while the 13F filer count keeps each CIK.