Form 13F: reconstruct positions without inventing trades
Reconstruct a Form 13F position table by applying amendment instructions, preserving security type and resolving other-manager references. Do not concatenate every downloaded row. The objective is a coherent quarter-end disclosure object, not a transaction history or an estimate of the manager’s complete economic exposure.
Read amendment meaning before merging
The SEC staff’s Form 13F FAQs, particularly questions 58b and 58c, distinguish a restatement from an amendment adding holdings. The same guidance discusses options, investment discretion and other managers. This article concerns US Form 13F and its reported securities population; it does not treat another country’s ownership filing as an equivalent table.
Record manager identity, reporting quarter, amendment number, amendment type and accession. An amendment publication date does not create a new quarter-end observation. A restated complete table and an additions-only table require different merging operations. Keep the original files so the reconstruction can be explained without overwriting history.
Hypothetical three-document chain
Assume an original filing reports 600 common shares of fictional Issuer A. Amendment one is explicitly a restatement and corrects that line to 550. Amendment two explicitly adds an omitted holding of 50 common shares of Issuer B. All quantities and issuers are hypothetical.
The reconstructed common-share population is A 550 and B 50, not A 1,150 plus B 50. The original A 600 is superseded for the current corrected view. It remains useful for a historical account of what the first filing said, with the original cutoff preserved.
| Document role | A common shares | B common shares | Reconstruction action |
|---|---|---|---|
| Original table | 600 | Not reported | Starting version |
| Restatement | 550 | Not reported | Replace corrected table |
| Additions-only amendment | Not included | 50 | Add specified new holding |
| Current reconstructed view | 550 | 50 | Keep document lineage |
Now assume an additional line reports call options over 100 underlying A shares. Preserve the CALL indicator and relevant units. Adding those 100 to A’s 550 common shares and calling the result 650 common shares would erase the security distinction. The form’s option information does not by itself provide an option premium, delta or a complete risk-equivalent share count.
Resolve other-manager references
Suppose a shared-discretion line for 200 of A’s shares references another included manager. That does not automatically mean another 200 should be added to the reconstructed total. Determine whether those units are already part of the reporting table and how the related manager reports them. The table’s manager-number references and summary information are evidence for this scope check.
Build a key using manager, quarter, issuer identifier, security class, put-or-call flag and relevant discretion fields. A key based only on issuer name can collapse genuinely different lines. Conversely, treating a filing accession as the entire economic identity prevents corrections from replacing the rows they correct.
Perform reconciliation checks
Compare the reconstructed entry count and reported value totals with the relevant cover and summary pages, while retaining amendment-specific scope. Never use a mismatch as permission to invent an omitted security. Check XML values, units and the precise summary definition before assuming an error.
Observable triggers include an additions-only amendment, confidential-treatment release, changed manager relationships and inconsistent option flags. A missing row can mean outside scope, omitted information or a changed position; the form alone does not identify a sale date.
The final worksheet should provide the active rows, superseded rows, amendment operation and unresolved manager overlaps. It can explain a position reconstruction while declining to fabricate trades. This is different from measuring disclosure age: even a perfectly dated filing can be merged incorrectly if its amendment and instrument semantics are ignored.
Retain a reconstruction-operation column in the exported table. That allows another researcher to distinguish an active corrected row from a superseded row without guessing from file dates.
FAQ
Should every 13F amendment replace all earlier rows?
No. Follow its stated amendment type and chain; additions-only amendments and restatements play different roles.
Are call-option underlying shares ordinary shares held outright?
No. Preserve the option flag and avoid combining different security types into an unsupported ownership total.