Big investment managers have to show what they own, and short sellers' positions are published too. Together they tell you who's betting on a stock, and who's betting against it. Both come with delays and blind spots that change how much they can tell you.
What a 13F filing is
In the US, investment managers with more than $100 million in certain securities must file Form 13F with the SEC every quarter, listing their US stock holdings. Hedge funds, mutual fund companies, pension managers and banks all file them.
They're due within 45 days after the end of each quarter. So a 13F filed in mid-May shows holdings as of March 31: by the time you read it, the positions can be two to four months old, and the manager may have sold everything since.
What 13Fs can tell you
- Who owns the stock, and how concentrated ownership is.
- Quarter-to-quarter change: are institutions, in total, adding to the stock or trimming it?
- Buyers versus sellers: how many managers increased their positions against how many cut them.
- Notable investors opening or closing a position (useful as a lead, not a reason).
What 13Fs don't tell you
- Anything current. The data is a snapshot from the end of the last quarter.
- Short positions. 13Fs cover long positions only, so a fund that's hedged or betting against the stock can look like a buyer.
- Why. A fund may buy because the stock joined an index it tracks, not because anyone likes it.
- Non-US holdings and many smaller managers.
Because 13F data only changes once a quarter, it says much more about the medium and long term than about next week.
Short interest: who's betting against it
Short interest is the number of shares sold short (borrowed and sold, by traders hoping to buy them back cheaper). It's reported twice a month, so it's fresher than 13F data. It's usually shown as a percentage of the shares available to trade (the float).
- Rising short interest means more traders are betting on a fall.
- Very high short interest (say over 20% of the float) means a crowded bet against the stock, which carries its own risk.
Days-to-cover and squeezes
Days-to-cover is short interest divided by the average daily trading volume: how many days of normal trading it would take for every short seller to buy back. A high number means short sellers would struggle to exit quickly.
If good news pushes the price up, short sellers may rush to buy back at once, pushing it up further. That's a short squeeze. High short interest plus high days-to-cover means squeeze risk, which can cut both ways: violent rallies, and violent falls after them.
How to read the two together
- Direction of institutional change: are funds, in total, adding or trimming, quarter over quarter?
- Breadth: are more managers buying than selling?
- Short interest trend: rising or falling, and how high?
- Days-to-cover: is there squeeze risk?
- Remember the dates: discount the 13F picture more the further you are from the quarter it describes.
How Ticker Council uses this data
The Institutional Holdings seat on Ticker Council sees only 13F holdings and their quarter-over-quarter change, ETF inclusion, short interest and days-to-cover. The direction of its lean is worked out in code from the filings themselves (the change in institutional shares, buyers against sellers, and a short-interest and days-to-cover check for squeeze risk), so it doesn't read the same numbers two different ways on two runs. The AI then sets how strong the lean is for each period and explains it, discounting for the 13F delay, more so for next week than for the year.
Not financial advice: this guide explains public filings, not what to buy or sell.
Questions
What is a 13F filing?
A quarterly report that US investment managers with over $100 million in certain securities file with the SEC, listing their US stock holdings. It's due within 45 days after each quarter ends.
How old is 13F data?
It shows holdings as of the last quarter-end and can be filed up to 45 days later, so when you read it the positions can be two to four months old.
What does high short interest mean?
That many traders are betting the stock will fall. Combined with high days-to-cover, it also means squeeze risk: if the price jumps, short sellers buying back at once can push it higher still.
What is days-to-cover?
Short interest divided by average daily trading volume: roughly how many days of normal trading it would take for all short sellers to buy back their shares.