Methodology

Data Sources & How We Compute Whale Analytics

Last updated: October 5, 2026

This page documents where Whale Analyzer's data comes from, how the derived analytics on each stock and investor page are calculated, and — importantly — the limitations of working from public disclosures. Transparency about method is part of being a trustworthy research tool.

Primary data source: SEC 13F filings

According to the SEC's Form 13F FAQ, an institutional investment manager generally becomes subject to Form 13F reporting when it exercises investment discretion over US$100 million or more in Section 13(f) securities, measured on the last trading day of any month during the calendar year. This is not a threshold based on the manager's total assets under management.

The filing reports specified positions as of a calendar-quarter end, including the security class, share or principal amount, and reported fair market value. Reportable securities are defined by the SEC's quarterly Official List of Section 13(f) Securities. The list mainly includes U.S. exchange-traded stocks, closed-end funds and ETFs, and also includes certain convertible debt, options and warrants. We obtain filings from SEC EDGAR for the reporting entities tracked on this site.

Dates matter: Form 13F is generally due within 45 days after quarter end. The report date is the quarter-end snapshot; the filing date is when the submission became public. A later collection date or price date does not make the reported holdings current.

Other disclosure sources

Profiles based on SEC ownership filings, insider filings, or political financial disclosures use different reporting rules and are labeled separately. We do not treat those records as 13F portfolios. Political transaction reports commonly disclose a transaction date and an amount range rather than an exact trade value; a reported range is preserved as a range and does not establish a current portfolio, cost basis, performance, or net worth. Where a profile has no usable local record, it remains a discovery entry rather than a complete portfolio.

Dates and price data

Interactive stock pages read the latest available quote snapshot and display its market timestamp when supplied by the quote source. A quote can be newer than the filing while the share count remains the older quarter-end disclosure. Historical daily closes are used only by the modeled-cost calculation below. Missing quotes or incomplete price history cause the affected metric to be omitted; they are not filled with invented values.

How the derived analytics are computed

Derived metrics describe the records available in Whale Analyzer's tracked sample. They do not describe every institutional holder or the entire market:

Tracked-sample concentration — for a stock page, reported values from matched tracked holders are summed, sorted, and used to calculate the largest holder and top-five or top-ten shares of that sample total. For an investor page, the same calculation uses positions within that filing. It is not total market ownership or a statement that the displayed holders "control" that percentage of the company.
Quarter-over-quarter activity — current and previous reported share counts are compared by ticker. A new position has no positive prior share baseline; an exited position falls to zero; increases and reductions are based on share-count direction. The summary counts tracked filers in each category.
Reported-value lists — "top buys" and "top sells" are position-change lists sorted using reported position values. Those values are quarter-end snapshots, not transaction proceeds or cash flows, so we do not present their sum as portfolio turnover.
Sector positioning — sector labels come from the current local holdings records. Peer lists cover other tickers found in the same tracked dataset, not a complete sector index.
Modeled cost comparison — when the model is complete and produces a positive estimate, a stock-level aggregate weights each included holder's modeled average cost by shares. It is compared with the latest available positive quote. Holders without a usable model are excluded from that calculation.

Modeled cost method

Form 13F does not report purchase price or execution date. For current common-stock positions with a usable quarterly history, our model replays changes in reported shares from the first observed quarter. For an increase, it adds the share change multiplied by the lowest daily close in that quarter. For a reduction, it subtracts the share change multiplied by the highest daily close in that quarter. A full exit remains in the running net-cost history if the ticker later reappears. Pure option positions are excluded. Quarters flagged as anomalous are skipped; if a required quarter has no price history, the record is marked incomplete and its modeled average cost is not displayed.

This deliberately mechanical model is neither the manager's tax cost basis nor a bound on the true cost, realized gain, unrealized gain, or investment return. The use of quarterly low and high closes can materially differ from actual execution prices. A displayed percentage is only the arithmetic difference between the latest available quote and the model estimate.

A reproducible example: market value is not cash flow

Suppose a filing reports 100 shares at US$10 per share at one quarter end, for US$1,000 of reported value. The next filing still reports 100 shares, but the quarter-end price is US$15, so reported value is US$1,500:

Share change: 100 minus 100 = 0 shares.
Reported-value change: US$1,500 minus US$1,000 = US$500.
Inference used here: the position is classified as held because reported shares did not change. The US$500 increase is not labeled a US$500 purchase or inflow.

If shares instead rise from 100 to 120, we can report a 20-share increase between snapshots. We still cannot recover the execution dates, prices, gross purchases, intervening sales, or cash spent from two quarter-end filings alone.

Update cadence

13F holdings are scheduled for quarterly refresh after public filings become available. Quote snapshots may update on trading days. Pages should be read using the dates shown on that page: report date for the holdings snapshot, filing date for publication, source-check or generation date for pipeline freshness, and market timestamp for a quote. These dates answer different questions and should not be substituted for one another.

Known limitations

Historical and incomplete. 13F omits short positions and securities outside the SEC's Section 13(f) list. Certain small positions may be omitted under the form's de minimis instruction, and confidential treatment can delay public visibility. The filing is not a manager's complete assets, exposures, trades, or current portfolio.
Tracked sample. Holder counts, aggregate values, concentration, activity and sector peers cover the filings and identifiers successfully matched by Whale Analyzer. They are not market-wide ownership statistics.
Identifier and amendment risk. CUSIP-to-ticker mapping, share classes, amendments, duplicate rows, stock splits and incomplete history can change a derived result. Use the linked filing as the controlling source.
Model limits. Modeled costs and quote comparisons are outputs of the assumptions above. They are not manager-reported purchase prices, P&L, returns or turnover.
Not investment advice. See our disclaimer. Nothing here is a recommendation to buy, sell, or hold any security.

Corrections

To report a reproducible issue, email leo.bikotech@gmail.com with (1) the Whale Analyzer page URL, (2) the reporting entity and report date, (3) the SEC filing URL or accession number, (4) the exact row or metric that differs, and (5) your expected calculation. A source-data error should be corrected in the relevant source metadata or parser and then propagated to derived pages; a presentation error should be corrected in the renderer. Our editorial standards explain the site's source-labeling and corrections principles.