May 27, 2026

How Biotechs Should Interpret and Use 13F Reports?

If you’re a public biotech and you want to know the institutional investors that own your stock, quarterly-filed Form 13Fs are one of the few reliable sources you can turn to. Once filed by funds with the SEC, they are then collectively repackaged by a host of partners such as your IR firm, investment bankers, and Nasdaq Equity Surveillance & Shareholders Analysis (if you are a subscriber) in the form of 13F reports.

This article follows on from our prior entry: “How Do Public Biotechs Know Who Owns Them? (And What are 13F, 13D and 13G Reports, and Transfer Agents/Registrars?”

Here, the focus is to help you interpret those various 13F reports and explain why – if you receive reports from more than one source – they may sometimes contain minor factual differences.

A reminder of what a Form 13F is and isn’t

A Form 13F is a quarterly disclosure filed by institutional investment managers who meet the reporting threshold (commonly understood as managing $100M+ in U.S. securities). The forms are filed within 45 days of each quarter-end, so the market typically sees fresh data in mid-February, mid-May, mid-August, and mid-November (all of which were accurate as of the respective quarter-end just passed).

Thus, a 13F report is not:

• A real-time cap table.
• A complete list of your shareholders.
• A measure of “sentiment.”
• A record of all buying and selling during the quarter (it simply compares quarter-end to prior quarter-end).

Instead, a 13F report is:

• A list of the buyers and sellers of your stock (quarter-end compared to prior quarter end) (often with a summary of your Top 10 Buyers and Top 10 Sellers) (and often going back eight quarters so that longer term themes and purchasing patterns can be discerned).
• A list of all your shareholders at the end of the most recent quarter who meet the SEC’s reporting threshold.

How to interpret and use 13F reports

1) Mentally separate active owners from passive funds and intermediaries

The easiest way to misuse a 13F is to treat every buyer, seller or holder you read about as equally “meaningful.” In most 13F reports, you’ll see a classification that effectively tells you what kind of shareholder you’re looking at.

Passive (index trackers): These are funds that buy and sell because of benchmark rules, not because of your data, your deck, or your CEO’s charm. They don’t have a fund manager you can persuade to “lean in” – they simply follow an index that includes your company.

Intermediaries (private banks, broker-dealers): When brokers appear on a 13F, it means they’re holding shares for someone else. They’re an intermediary, and we don’t know the beneficial owner(s) behind that line item. Confusing examples include Swiss banks, Wall St. banks, and even Fidelity – because each of these offer self-directed investment accounts to the public (as well as having active fund managers within their overall corporate family).

Active managers (mutual fund managers, hedge funds, etc.): These are the investors buying or selling your stock because of:

• Your investment thesis and outlook.
• Their meetings with management.
• Competitive readthroughs.
• Portfolio rebalancing choices they actively make.

Most 13F reports will break down active managers by their style of investment. This is often a moot point for development stage biotechs because terms like Aggressive Growth, Growth, GARP (Growth at a Reasonable Price), etc., aren’t meaningful without a growth metric (e.g., sales, EBITDA, etc.)

Familiarization with the categories of investment style is important, but not terribly useful in understanding why existing holders own your stock, or for shareholder targeting.

Key active manager investment styles

Category	Description
Aggressive Growth	Targets early-stage companies with very high growth, high multiples, no dividends, and higher trading turnover.
Growth	Invests in above-market growth companies but avoids extreme valuations; generally not yield-focused.
GARP (Growth at a Reasonable Price)	Seeks faster-growing companies trading at reasonable valuations; typically longer-term holders.
Value	Focuses on fundamentally strong companies trading at low valuations; long-term, lower-turnover approach.
Deep Value	Targets heavily discounted or out-of-favor companies with extremely low valuations.
Yield	Invests primarily for high and growing dividend income.
Specialty	Sector-specific or niche strategies that don’t fit standard style categories.
Alternative	Hedge funds using non-traditional or multi-strategy investment approaches.
Venture Capital	VC firms whose public holdings originate from pre-IPO investments.
Other	Non-investment firms, such as operating public companies.

Source: Ipreo, New Street Investor Relations

2) Don’t interpret selling too dramatically

When reading about who has bought and sold a biotech’s stock, management tends to assume that every fund selling them is, from that point on, unfriendly at best and traitorous at worst. This is not (always) so, and there are very good reasons for you to continue engagement.

Active managers may reduce their position for reasons that have nothing to do with you including:

• Liquidity needs.
• Year-end housekeeping.
• Profit-taking.
• Position sizing and risk limits.
• To finance redemptions from their fund.
• Rotation into another theme.

What a lot of biotech CEOs and CFOs forget is that – a fund that has made money buying (and then selling) your stock… is actually a form of intangible asset. Why? Well, having made money on you once, they are often more likely to be willing to invest again.

Buy-and-hold investors are great. Buy-sell-and-buy-again investors are just as valuable, especially when it comes to follow-ons.  So, stay engaged.

3) Use 13F reports to audit your investor targeting and IR effectiveness

Here’s a practical test every biotech should run:

• Pull your meeting list for the quarter just passed (from your CRM or your internal records).
• Compare it to the top buyers list in your 13F report.
• Ask: Did any of the investors we targeted actually show up as buyers?
• Also ask: Did any meaningful sellers meet with us and still sell?

If you’re conducting disciplined outreach, you should sometimes see the “fruits of engagement” show up in the buyer list. Not always, but sometimes. In addition, if selling resulted from poor communication or a misunderstanding, are there lessons to be learned?

4) Use the 13F report to evaluate your bankers, too

This one can make bankers uncomfortable, which is usually a sign it’s worth doing.

If the lead bank from your last financing told you they “placed the deal with high-quality, long-term funds,” and then the next quarter those funds liquidate, you should take note:

• Either those weren’t long-term funds.
• Or the allocation strategy favored fast money.
• Or the bank’s definition of “quality” is not the same as your definition of “quality.”

Make notes and refer to them when it’s time to pick the syndicate banks for your next follow-on, as well as when it comes to the allocations for that fundraising.

5) Expect late filers (and expect each report to “settle”)

In theory, 13Fs are due 45 days after quarter-end. In practice, you will sometimes see late filers, and occasionally you’ll see so many late filers that the report changes meaningfully over the next day or two.

This matters because it explains why:

• You might receive two versions of the report in the same week.
• Different providers (NASDAQ surveillance, a bank, databases such as Ipreo or IR Insight, etc.) might not match perfectly on day one (there may be timing issues).

6) Understand why 13F reports sometimes differ from each other

Speaking of which, even once all the data is in, 13F reports sourced from different partners will still sometimes differ slightly because of the way their data provider pulls and consolidates Form 13Fs.

Importantly:

• Do not waste time stressing about it.
• Do not start to question the legitimacy of the reports.
• There is usually a very simple explanation (that can potentially take days or weeks to uncover).
• Remember that all the data (however compiled and presented) comes from the same place – EDGAR.

7) Remember who won’t show up in 13Fs at all

Not every meaningful owner is a 13F filer. For example:

• U.S.-based fund managers whose assets are valued below the reporting threshold.
• Retail and larger beneficial owners sitting behind broker/custodian lines.
• Some foreign managers with insufficient U.S. exposure.

8) Set a practical “who matters” threshold

At some point, as you scroll through your ownership list or your list of buyers and sellers, you just get to noise (funds whose position simply don’t warrant management time/attention).

Instead, define a floor as a percentage of market cap (or a minimum dollar amount of ownership) aligned with how many investors you can realistically meet each year as part of a normal IR program.