# Is Copying Hedge Fund 13Fs a Good Strategy?

> What research says about cloning famous investors’ 13F filings, how much the 45-day lag costs, and where copycat strategies go wrong.

Source: https://www.exent.ai/resources/copying-13f-strategy · Reviewed by David, Senior Analyst, Exent · Published Nov 3, 2026 · Updated Nov 3, 2026

## Key takeaways

- Sometimes, with big caveats. One study found copying Berkshire’s disclosed buys beat the S&P 500 by 10.75% a year (1976–2006), but most managers are not Buffett and the edge depends on whom you copy.
- The 45-day filing deadline means you see a quarter-end snapshot up to about four and a half months after a trade, and the manager may already have sold.
- 13Fs leave out short positions, so a copied long can be half of a hedge you cannot see.
- Research on copycat mutual funds found clones matched high-fee funds after expenses, mainly because they skipped the fees.
- Copied ideas still have to fit your own portfolio’s risk, concentration and goals.

## What is 13F cloning?

13F cloning means buying the stocks a well-known manager discloses in their quarterly [13F filing](https://www.exent.ai/learn/13f-filing), usually at similar weights, and updating when the next filing appears. The appeal is simple: you borrow someone else’s research for free. The problems are also simple: you see it late, you see only part of it, and you do not know why the manager owns it.

## How late is a 13F?

A 13F can describe positions that are up to about four and a half months old. Per the [SEC’s Form 13F FAQ](https://www.sec.gov/rules-regulations/staff-guidance/division-investment-management-frequently-asked-questions/frequently-asked-questions-about-form-13f), filings are due 45 days after each calendar quarter ends, and they show holdings on the last day of the quarter.

| Event | Date (illustrative) | Days since the trade |
| --- | --- | --- |
| Manager buys | Jul 3 | 0 |
| Quarter ends: the snapshot date | Sep 30 | 89 |
| 13F filed on the deadline | Nov 14 | 134 |
| You buy after reading it | Nov 17 | 137 |

Illustrative timeline. A buy late in the quarter reaches you faster, and some managers file early, but you never see trades in real time. Insider trades on [Form 4](https://www.exent.ai/learn/form-4) arrive far faster, within two business days.

## What does the research say about copying 13Fs?

The academic evidence is more favorable than you might expect for a few managers, and weaker once costs and selection are considered.

| Study | Sample | Finding |
| --- | --- | --- |
| Martin & Puthenpurackal (2008) | Berkshire Hathaway, 1976–2006 | Buying each disclosed holding the month after disclosure beat the S&P 500 by 10.75% a year |
| Frank, Poterba, Shackelford & Shoven (2004) | High-expense mutual funds, 1990s | Copycat funds trailed before expenses but matched, and possibly beat, the originals after expenses |
| Cohen, Polk & Silli (Best Ideas) | US equity mutual funds | Managers’ highest-conviction stocks outperformed; most of their other holdings did not |
| Agarwal, Jiang, Tang & Yang (2013) | Hedge fund 13Fs, incl. confidential filings | Positions hidden through confidential treatment outperformed for up to 12 months |

Sources: [Martin and Puthenpurackal abstract](https://www.valuewalk.com/imitation-sincerest-form-flattery-warren-buffett-berkshire-hathaway/), [Copycat Funds (NBER)](https://www.nber.org/papers/w8653), [Best Ideas (LSE)](https://researchonline.lse.ac.uk/id/eprint/24471) and [Uncovering Hedge Fund Skill (Journal of Finance)](https://ideas.repec.org/a/bla/jfinan/v68y2013i2p739-783.html).

Read together, they say three things. A truly skilled, slow-moving manager can be worth copying even late. Much of a clone’s advantage over a fund comes from not paying its fees. And the most informative positions are the ones you are least likely to see: concentrated best ideas and holdings kept confidential.

## Why do copycat portfolios disappoint?

- Selection bias: you pick managers because their past returns were great, which is the period you can no longer earn.
- Turnover: for fast-trading funds, a quarter-end list is stale before it is published.
- Missing shorts and options: a long stock may be hedged, so copying only the long side takes on risk the manager did not.
- Different constraints: a fund may hold a stock for liquidity, index tracking or client reasons that do not apply to you.
- Crowding: when many investors copy the same filings, the most popular names can get expensive.
- Concentration: copying one manager’s top five positions can leave you with far more single-stock risk than you intended.

## If you use 13Fs, what makes it more sensible?

Investors who use 13Fs as an input, not a blueprint, tend to follow a few rules:

- **Prefer slow, concentrated managers.** Low turnover means the quarter-end snapshot stays relevant longer.
- **Focus on new positions and large adds.** These are closer to a manager’s best ideas than a long tail of small holdings.
- **Look for agreement.** A stock that several unrelated managers added, with insider buying on top, is a stronger lead than one fund’s position.
- **Do your own homework.** Write the thesis without the manager’s name. If it does not stand up, skip it.
- **Size for your portfolio.** Check how the idea correlates with what you already own before adding it.

A broader routine is in [how to track smart money](https://www.exent.ai/resources/how-to-track-smart-money), and other places to find ideas are on [stock ideas](https://www.exent.ai/ideas).

## So, is it a good strategy?

As a complete strategy, copying 13Fs has more ways to go wrong than right for most investors: late data, hidden hedges and the risk of copying last decade’s winner. As a source of ideas to research, it is useful and free. Before relying on any manager, check how their disclosed picks actually performed: [how to measure a fund’s 13F returns](https://www.exent.ai/resources/smart-money-returns).

## How to research 13F ideas with Exent

1. Stocks Radar shows 13F, insider and congress views on each stock, next to analyst ratings ranked by past accuracy.
2. Gems flag stocks where several of the best-rated analysts agree: a second, independent check on an idea.
3. Upload your holdings and add the idea in the what-if simulator to see how concentration and correlation clusters would change.

Exent is our product: [Exent Gems](https://www.exent.ai/radar)

## Frequently asked questions

### Does copying Warren Buffett’s 13F work?

A 2008 study found that buying Berkshire’s disclosed holdings the month after disclosure beat the S&P 500 by 10.75% a year from 1976 to 2006. That is a past result for one exceptional, slow-moving investor, not a forecast.

### How delayed are 13F filings?

They are due 45 days after each quarter ends and show holdings on the quarter-end date. A trade made early in a quarter can become public more than four months later.

### Do 13F filings show everything a hedge fund owns?

No. They show long positions in US-listed securities. Short positions, most non-US holdings, cash and some confidential positions are not included.

### Are there ETFs that copy hedge fund 13Fs?

Some funds build portfolios from 13F data. They face the same lag and missing-shorts problems, plus their own fees, so check their record against a simple index fund.

### Which managers are easiest to follow through 13Fs?

Those with concentrated, long-only portfolios and low turnover. For quantitative or multi-strategy firms, a quarter-end list says little.

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Educational content, not investment advice. Past performance does not guarantee future results.