Limitations of 13F data
13F data is dated by up to 45 days, covers only long positions in US-listed securities, omits shorts and most derivatives, and can be amended after the fact. It tells you what a manager owned on one day per quarter, not what they own today or why. Used with those limits in mind it is still the only public, audited record of institutional positioning.
How stale is 13F data?
A position dated 30 June is typically published on 14 August and may have changed the day after quarter end. For high-turnover managers the snapshot can be unrepresentative; for low-turnover investors such as Berkshire Hathaway it remains informative. Fundocap shows the quarter-end and filing dates on every guru page and computes "time held" so you can tell the two apart.
What positions are missing?
Short positions, credit default swaps, futures, most OTC derivatives, bonds, cash, non-US listings and private holdings. A 13F portfolio value is therefore not the fund's assets under management, and a large long position can be part of a pair trade or hedge that the filing does not show.
Why do share counts jump?
Stock splits change share counts without any trade. Fundocap adjusts historical share counts with a splits table where it has split data and labels those tables split-adjusted; where it does not, a 4-for-1 split looks like a 300% increase. Mergers, spin-offs and ticker changes cause similar breaks.
Can filings be wrong or changed?
Yes. Managers file amendments (13F-HR/A) that restate a quarter, occasionally weeks later. Some request confidential treatment and disclose positions only after the SEC decision. Fundocap keeps the most recently filed document for each quarter, so an amendment replaces the original.
What does this mean for copying a portfolio?
You buy at least 45 days late at different prices, cannot see the hedges, and cannot see the sizing logic. Copying works best for concentrated, low-turnover managers with long holding periods; it works worst for quantitative or multi-strategy funds. The consensus and conviction rankings are designed around that distinction.
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Frequently Asked Questions
Does 13F show what a fund owns today?
No. It shows quarter-end positions published up to 45 days later. Anything since then is invisible until the next filing.
Why is Berkshire's 13F value different from its total assets?
The 13F covers US-listed equities only. Operating businesses, cash, bonds and foreign listings are outside the filing.
13F data shows quarter-end positions, is delayed by up to 45 days and covers only long positions in US-listed securities; short positions, most derivatives and non-US assets are not reported.