Press
Press and creators: GestorLens data you can cite
If you write about markets and need a figure on what institutional managers reported to the SEC, here is what you can use and how to credit it.
What GestorLens is
GestorLens organises and explains, in Spanish and English, the documents that institutional managers and companies file with the US SEC: quarterly portfolios (13F), stakes above 5% (13D and 13G) and insider transactions (Form 4).
It is a personal, independent project by Cristian Díaz. It is not an investment firm and gives no advice: it describes what was reported, with the date of the data and the source document, and does not recommend buying or selling.
Coverage: 47 well-known investors with their own page · 703 concentrated managers · 8,931 managers with a current portfolio.
Citable figures for Q2 2026
Portfolios as of June 30, 2026, public by August 14, 2026 (the 13F filing deadline). These sentences update themselves every quarter.
In Q2 2026, the stock most managers added was Advanced Micro Devices (AMD): it went from 54 to 79 concentrated managers' portfolios (+25). Among those who already held it, 5 added and 30 trimmed. Next came Intel (INTC, +23) and Micron Technology (MU, +21). It counts managers, not dollars or shares. The figures come from the 13F filings of 703 concentrated managers, with portfolios as of June 30, 2026.
See the full list →In Q2 2026, the stock most managers dropped was Intuit (INTU): it went from 63 to 43 concentrated managers' portfolios (−20). Among those who already held it, 11 added and 20 trimmed. Next came Microsoft (MSFT, −10) and Netflix (NFLX, −10). It counts managers, not dollars or shares. The figures come from the 13F filings of 703 concentrated managers, with portfolios as of June 30, 2026.
See the full list →In Q2 2026, Seagate Technology Holdings (STX) leads the buying overlaps among well-known investors: Stanley Druckenmiller, Tiger Global and Lone Pine bought it and none of them sold. On the selling side, Lam Research (LRCX): 4 of them sold (Tiger Global, Coatue, Ray Dalio and Jeremy Grantham). The stock that split them most was Alphabet (GOOGL): 7 bought and 9 sold.
See the full list →
Q3 2026 season data for the media
Who has filed their 13F, when, the value and positions reported and their three largest weight changes; the well-known investors' calendar (filed or estimated date) and the stocks most concentrated managers bought and sold so far. They are the same figures as the season page, without market prices, and they refresh as 13Fs come in. The deadline is November 16, 2026: until then the data is partial.
- Season data (CSV, for a spreadsheet)
- Season data (JSON, for a program)
- 13F deadlines and estimated dates (.ics calendar)
- Atom feed: 13F filings by well-known investors
- Atom feed: all SEC updates (13F, 13D/13G, Form 4)
Licence: CC BY 4.0, crediting “GestorLens (gestorlens.com), with SEC data”. In Spanish: CSV · JSON.
The study, in two paragraphs
An analysis by GestorLens of every Form 13F filed with the SEC between 2013 and 2025 (129,534 observations of 8,228 stocks; one observation is one stock in one quarter) found that the average stock held by concentrated managers returned, in the twelve months after the filing became public, 3.7 percentage points less than the S&P 500 (average of quarters: every quarter weighs the same; the gap is not statistically significant, t = −1.56), and that only 40% of cases beat the index. It measures a simple average of the stocks held, not copying a portfolio with its weights.
The most consistent result was the negative one: stocks no manager had been adding to lagged the rest of the group. Among those being accumulated, the gap in their favour grew with the time of accumulation (from +0.5 to +2.2 points versus the rest), but the group with four or more quarters does not reach the usual statistical threshold, and it was still not enough to beat the index. The study measures from the actual publication date of each filing, includes companies that stopped trading and excludes costs, taxes and dividends (price return only). Past results do not anticipate future ones.
Díaz, C. (2026). Does copying superinvestors work? 129,534 cases since 2013. GestorLens. https://www.gestorlens.com/en/estudios/sirve-copiar-superinversores
The studies, with their data
Each study has its page, the full report as a PDF and the data behind every chart as CSV, under the same licence.
When the 13F arrives and what arrives late
48% of concentrated managers' 13Fs are filed on the last business day of the filing window, and part of the portfolios shows up months later, by amendment.
The average overlap between two concentrated portfolios went from 2.15% to 3.97%. Excluding the 10 highest-value stocks, from 1.55% to 1.83%.
Three in ten new positions no longer appear in the next 13F
Of every 10 positions that appear for the first time in a concentrated manager's 13F, about 3 are missing from the next one (29.2%) and about 6 are gone a year later (59.4%).
Does copying superinvestors work?
- Working paper (PDF, Zenodo) · DOI 10.5281/zenodo.23324670
- CSV · Every signal and group
Open data repositories
- Zenodo · Working paper and observations of the copying study · DOI 10.5281/zenodo.23324670
- Kaggle · copying study · Dataset
- Kaggle · the three reports · Dataset
- Kaggle · notebook: rebuild the headline figure · Notebook
- Kaggle · notebook: overlap, persistence and timing · Notebook
- Hugging Face · copying study · Dataset
- Hugging Face · the three reports · Dataset
How to cite
The download files and the study (with its tables, charts and observations) are published under Creative Commons Attribution 4.0 International (CC BY 4.0): you may use, copy, adapt and redistribute them, including commercially, with attribution (“GestorLens (gestorlens.com), with SEC data”). The original SEC documents are in the public domain. The rest of the site, the GestorLens brand and the design are not under that licence. This is not investment advice. There is no need to ask for permission. The detail is in the data licence (CC BY 4.0).
Source: GestorLens (gestorlens.com), with SEC data.
Mistakes to avoid when citing a 13F
- It is not real-time buying. A 13F is the portfolio at quarter end (Mar 31, Jun 30, Sep 30 or Dec 31), not what the manager is buying today.
- It arrives up to 45 days late. It is filed up to 45 days after quarter end: by the time it is public, the portfolio may have changed.
- The firm files it, not the person. The accurate wording is “Berkshire Hathaway reported”, not “Buffett bought”.
- It does not show the whole portfolio. It leaves out short positions and cash, and stocks not traded in the US; an option does not say whether it was bought or sold.
- “Reduced” is not “sold everything”. And a confidential position may show up months later, in an amendment.
Citation templates
Copy them and fill in the brackets. Quarter-end and filing dates are on every page of the site.
News article
According to the Form 13F that [firm] filed with the SEC on [filing date], its portfolio as of [quarter-end date] [figure]. Source: GestorLens (gestorlens.com), with SEC data.
Social media
[Firm] reported its portfolio as of [quarter-end date] to the SEC (13F filed on [date]): [figure]. Via @GestorLens · gestorlens.com
Newsletter
[Figure], according to [firm]'s 13F with its portfolio as of [quarter-end date]. Source: GestorLens (gestorlens.com), with SEC data; CC BY 4.0 licence.
Citing the season data
GestorLens (2026). Q3 2026 13F season [dataset]. https://www.gestorlens.com/prensa/datos/13f-season.csv. Retrieved [date]. CC BY 4.0 licence.
Image or chart caption
Chart: GestorLens (gestorlens.com), with SEC data.
Downloadable material
- GestorLens logo as SVG: for light backgrounds · for dark backgrounds · icon only
- GestorLens logo (PNG, 512 px)
- Photo of Cristian Díaz (JPG, 640 px) · WebP
Images ready for articles
The social images of each page (investor, stock, season, topics) are public and update with the data: they may be used with the same source credit. They are 1200 × 630 px (PNG), carry the brand and the source, and follow the same pattern: /og/inversor/<name>, /og/accion/<ticker>, /og/temporada/actual (add ?l=en for English).
Contact
For a specific figure (an investor, a stock, a sector) or a question, write to contacto@gestorlens.com.
Research information built from public SEC documents. Not investment advice.