How 13F amendments are combined

Method H3. Version 1.1, 2026-10-05.

A quarter is the latest original or restatement plus every NEW HOLDINGS amendment filed after it.

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

The position of a filer in a quarter is the latest of its original report and its RESTATEMENT amendments, plus every NEW HOLDINGS amendment filed after it, in filing order (filing date, then amendment number, then accession number). A restatement replaces the whole report. A NEW HOLDINGS amendment adds rows to it.

• A NEW HOLDINGS amendment that repeats the original is a restatement filed under the wrong type. It is read as a restatement when either holds: it repeats at least half of the base report's positions, or it is at least 90% of the base report's size with a total value within 1% of the base's.
• A 13F-HR/A with no amendment type is read as a restatement.
• A NEW HOLDINGS row identical to one already in the quarter (same security, put or call, principal flag and amount) is not added twice.
• NEW HOLDINGS with no original loaded: when no original or restatement for the quarter is in the data, the amendments stand alone as the quarter's positions. The fund page says so and names the latest of them as the source.

How often

The SEC data set 01jun2026 to 31aug2026 has 258 restatements (232,005 rows) and 141 NEW HOLDINGS amendments (16,390 rows) on 13F-HR/A (DS §1.4). Across both 2026 data sets, of 244 NEW HOLDINGS amendments 48 read as restatements (47 by overlap, 1 by size and total), 85 were added to their quarter, 102 had no original loaded and stand alone, and 9 were superseded by a later restatement. 83 repeated rows were dropped.

Worked example

Mountaineer Partners Management, LLC filed its 13F-HR for the quarter ended 2026-06-30 on 2026-08-13 (0000919574-26-005107), with 11 positions after rows are summed. On 2026-08-14 it filed a 13F-HR/A of type NEW HOLDINGS (0000919574-26-005443) with one row: 1,148,027 shares of Ardagh Metal Packaging (AMBP). The original already listed 574,207 AMBP shares. One row is far under half of the base's 11 positions and far under 90% of its size, so the amendment is no restatement, and the quarter adds the two: the Q2 2026 page shows 1,722,234 AMBP shares and lists both filings with their roles.

What this does not do

• It never drops a filing silently. Every fund quarter page lists each 13F of the quarter as base, added or superseded.
• It never mixes quarters: a filing counts for the period it reports, whichever data set it arrived in.