How the ETF Ownership Index is computed

Edited by VoidLab Data through 2026-10-13 Last revised 2026-10-13

The TickerInside ETF Ownership Index measures, for each US-listed company of the ETF ownership ledger, how much of its shares the covered US ETFs hold, how much of that holding sits in the three funds holding the most, and how it moved over the last 5 and 20 market days; then the same over the market and by sector, weighted by market cap. In the index of 2026-10-13, 3,610 stocks have a figure, and the covered US ETFs hold at least 11.41% of the combined market value of the 3,503 companies measured. The method is ti-ownership-index/1. It reads the figures of the ownership ledger (ti-ownership/1) and of the ETF flows (ti-flows/1), and no other source.

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What does the index measure?

Four figures for each stock and the same over groups of companies. Every one names the method that produced it and the dates of what it counts.

Ownership, pct_lower_bound: The share of the company's shares outstanding held by the covered US ETFs, from the SEC's count of shares outstanding: the figure of the ETF ownership ledger, ti-ownership/1, a lower bound.
Concentration, top3_share_pct: The share of the counted funds' holdings that the three funds holding the most hold. A fund holding two classes of the company is one fund, each class at its weight.
Change, change_5d_pp and change_20d_pp: How the ownership moved over the last 5 and 20 market closes, in percentage points of the shares outstanding, from what the funds read daily from their issuers' files bought and sold.
Lines, market and sectors: Over one line per company: the share of the companies' combined market value held by the covered US ETFs, weighted by market cap, the mean, the median and the quartiles of their figures, and the cap-weighted change.

What are the formulas?

For one company, with shares_held the sum over the counted funds of the shares each holds of every listed class at its weight, h₁ to h₃ the holdings of the three funds holding the most, and net_shares(c) what the funds read daily bought less what they sold on close c:

pct_lower_bound  = floor(100 x shares_held / shares_outstanding, 2 decimals)
top3_share_pct   = round(100 x (h1 + h2 + h3) / shares_held, 1 decimal), with 6 funds or more counted,
                   null where a published sum would give back one fund's count
change_nd_pp     = round(100 x sum of net_shares(c) over the last n closes / shares_outstanding, 4 decimals)

Over the companies i of a line, each with its figure pct_i and its market cap cap_i:

cap_weighted_pct = floor(sum of pct_i x cap_i / sum of cap_i, 2 decimals)
change_nd_pp     = round(sum of change_i x cap_i / sum of cap_i, 4 decimals), over the companies with a change

On a company basis, the change sums the net shares of every listed class at its weight, as the ledger sums the shares held. The method, ti-ownership-index/1, is written in methods.json beside the ledger's, with test vectors to check an implementation against.

How are one stock's figures worked out?

In the ledger of 2026-10-13, the covered US ETFs hold 2,739,902,996 shares of Nvidia (NVDA), counted from 745 funds whose holdings are dated 2026-05-29 to 2026-10-13. The SEC's count of its shares outstanding, as of 2026-08-21, is 24,100,000,000. 100 x 2,739,902,996 / 24,100,000,000 = 11.3689, rounded down to two decimals: 11.36%.

The three funds holding the most hold 34.6% of the 2,739,902,996 shares counted, so the other 742 funds hold 65.4%.

Over the 5 market closes from 2026-10-06 to 2026-10-12, the funds read daily bought 4,376,647 shares more than they sold, as the flows publish their daily sums. 100 x 4,376,647 / 24,100,000,000 = 0.0182 percentage points: the change_5d_pp of NVDA. These two figures come from the archive of the issuers' files and are under the history terms.

Every figure above is in the stock's file, under etf_ownership, in ownership-index.json and in the daily history. The funds that hold it, with their weights, are on its page.

Where do the figures come from?

Shares held: the covered funds' own files, the issuers' daily holdings files for the funds they publish, and the latest SEC Form N-PORT filing for the funds no issuer file covers. Each figure gives the oldest and newest dates of the files it counts.
Shares outstanding: the cover of the company's latest 10-K, 10-Q, 20-F or 40-F, in the SEC's XBRL data, with its date and the filing it comes from.
Net shares: the ETF flows, ti-flows/1, read from consecutive files of each fund read daily, each file placed at the market close it reflects. A daily sum is published when three funds or more make it and no one fund more than 80% of it, and the lines that are no trade are left out of it: a split, a merger, a spin-off, a change of ticker, a line a file dropped for a day.
Market caps: the market data's, at the price date, used as weights of the lines only. They enter no stock's figure.
Sectors: the price data's, for the companies of its S&P 500 list.

What are its limits?

The figure is a lower bound. ETFs outside the coverage are not counted, nor covered funds whose share count cannot be used, and the percent is rounded down. One exception: a count of shares outstanding is used when it is at most 2% below a current independent count of the same shares, so a figure can be up to about 2% of itself too high.
The holdings and the count of shares outstanding carry different dates, both published with each figure. A fund known from its SEC Form N-PORT filing is counted as its filing reports it, months before the issuers' daily files.
The change counts the 623 funds read daily from their issuers' files that the flows count. The funds known from SEC filings are not in it.
The change ends on the flows' latest close, 2026-10-12, which can be a close before the ledger's newest holdings date, since each file is placed at the market close it reflects.
A change is null when a daily sum of its window is withheld by the flows' rules, when the flows name a corporate action of the stock within the window or 3 closes before it, when a close of the window is not a complete close of the flows, and when no fund read daily held or moved the stock.
The concentration is published when 6 funds or more are counted and no sum the stock file publishes gives back one fund's count by difference with it: the funds read from issuer files among the three largest, and those beside them, by layer and by class, must each be none or a sum over 3 funds or more, no fund above 80% of it.
A figure of one class alone is in the rows of the stocks and left out of the market and sector lines, since a class's percent is not the company's. A company without a market cap is in the mean and the quartiles and left out of the cap-weighted figures.
A sector has a line when it has 5 companies or more. The sector is the price data's, which covers the companies of its S&P 500 list; the other companies are in the market line only.
The daily history starts on 2026-09-29, the first complete close of the flows, since the issuers' files carry share counts from late September 2026. A row is written the first night its close is published and never rewritten; the rows before the first night are rebuilt from the flows of that night, with their changes and no levels.
Tonight the 20-day window, from the close of 2026-09-14 to 2026-10-12, is not covered by complete closes of the flows, so every change over it is null.

Where is the index as data?

/api/v1/ownership-index.json and /api/v1/ownership-index.csv give every stock's row and the market and sector lines, under CC BY 4.0. /api/v1/ownership-index/history.json and /api/v1/ownership-index/history.csv give the lines by market close and each stock's change over 1, 5 and 20 market days; they are computed from the archive of the issuers' files and are under the history terms. The highest figures are listed on ETF ownership, and every field is described on the API page.

Cite this page

TickerInside, ETF Ownership Index methodology, ti-ownership-index/1, index of 2026-10-13, https://tickerinside.com/etf-ownership/methodology/, CC BY 4.0

<a href="https://tickerinside.com/etf-ownership/methodology/">TickerInside</a> (https://tickerinside.com/etf-ownership/methodology/)

Index of 2026-10-13. Measurements of what funds hold, not investment advice.