Draft for review — not published yet
What a 13F is
In the United States, institutional investment managers with investment discretion over at least $100 million in certain U.S.-listed securities file Form 13F with the SEC every quarter, within 45 days after the quarter ends. The filing lists each position’s issuer, number of shares and market value on the last day of the quarter. Filings are public on SEC EDGAR.
The securities covered are mostly U.S. exchange-traded stocks and ETFs, plus listed options and some convertible bonds. The SEC publishes the official list each quarter.
What it leaves out
- Short positions. They are not reported. A fund that owns a stock and is short even more of it shows up as a buyer.
- Most of the rest of the portfolio. Non-U.S. holdings, most bonds, cash, private investments and many derivatives, such as swaps, are outside the form.
- Timing. It is a photo of the last day of the quarter. Trades during the quarter, and positions opened and closed between two quarter-ends, never appear.
- Freshness. Filed up to 45 days after the quarter ends, a position can be four and a half months old by the time you read it.
- Prices paid. Not reported. Values are at quarter-end prices.
- The shape of option bets. Options are reported as the underlying shares, which says little about the bet. A put can be a hedge as easily as a bearish view.
- Some positions, on purpose. Small holdings can be left out, and managers can ask the SEC to keep certain positions confidential for a time.
Common misreadings
- “The fund bought it.” It may be an index rebalance, the long side of a pair trade, or a client flow at a multi-strategy firm.
- “Funds are selling.” Managers reorganize, merge or stop filing. A naive total counts that as selling.
- “I’ll copy the trade.” By the time the filing is public, the manager may already be out.
How TREDIA uses 13F data
- Consensus, not copying. TREDIA reads the filings of a curated set of large managers and shows where they agree: what is most widely held, most bought and most sold.
- Like with like. Quarter-over-quarter changes are measured only on managers that filed in both quarters, each against itself. Managers that reorganized, merged or stopped filing are left out of the percentage and counted separately as opened or closed positions.
- Dates in view. Every screen shows the filing quarter, so a number from March is never mistaken for one from today.
The same caution applies to the U.S. congressional trades in TREDIA. They are legally reported in ranges, not exact amounts, and can arrive up to 45 days after the trade.
A 13F is good evidence of conviction and rotation among large managers. It is not a list of trades to follow.
For research and education. Not investment advice.