How to Read a 13F Filing: A Step-by-Step Guide

A Form 13F can look like a dense regulatory table, but the core questions are straightforward:

• Who filed it?
• Which quarter does it cover?
• What securities were reported?
• How many shares were reported?
• How large was each position?
• What changed from the previous quarter?
• What can—and cannot—be concluded from those changes?

The biggest mistake is to read a 13F as if it were a live brokerage account.

It is not.

A 13F is a historical quarter-end disclosure of certain reportable securities. It is useful for studying institutional portfolio structure and changes, but it does not show every asset, every trade, or the manager's current holdings in real time.

If you are new to the filing itself, start with What Is a 13F Filing?. This guide focuses on how to read one.

Before looking at any stock, find the reporting period.

A filing may show:

Period of Report:
2026-06-30

That means the holdings in the information table relate to the end of the calendar quarter on June 30, 2026.

This is the first date that matters.

It tells you when the portfolio snapshot applies.

Do not confuse it with the filing date.

Next, find when the filing was submitted to the SEC.

For example:

Period of Report:
June 30

Filing Date:
August 14

The reported holdings describe June 30, not August 14.

That distinction matters because Form 13F is generally filed within 45 days after the end of a calendar quarter.

By the time you read the filing, the manager may already have changed the position.

A careful description is:

> The manager reported the position as of June 30.

Not:

> The manager owns this position today.

You may encounter filing types such as:

13F-HR
13F-HR/A

A 13F-HR is a holdings report.

A 13F-HR/A is an amendment to a previously filed holdings report.

If you see an amendment, do not automatically rely on the earlier version.

Check whether the amendment:

• restates prior information;
• adds holdings entries;
• corrects reported data;
• changes other filing details.

When comparing quarters, use the most appropriate final filing for each reporting period.

Otherwise, you can create false changes simply because you compared an amended quarter with an outdated original filing.

The cover page identifies the institutional investment manager filing the report.

Check:

• manager name;
• address;
• Form 13F file number;
• report type;
• whether other managers are included.

This matters because the legal reporting entity may not always match the brand name investors use.

A well-known investment organization can have:

• multiple legal entities;
• affiliated advisers;
• sub-advisers;
• multiple filing managers.

Before concluding that two filings belong to the same investment operation, confirm the filer identity.

Form 13F can distinguish among different report structures.

A filing may identify itself as a:

• 13F Holdings Report;
• 13F Notice;
• 13F Combination Report.

A holdings report indicates that the filing manager reports the relevant holdings in the report.

A notice can indicate that the manager's holdings are reported by another manager.

A combination report can involve a mix of holdings reported directly and holdings reported by another manager.

For ordinary holdings analysis, do not assume that every filer page should contain a full standalone list of securities.

The report type tells you how the filing is structured.

The summary page gives you a quick sense of scale.

Useful fields include:

Information Table Entry Total
Information Table Value Total
Number of Other Included Managers

Suppose you see:

Information Table Entry Total: 120
Information Table Value Total: $25 billion

That tells you the filing contains 120 reported entries with a combined reported value of roughly $25 billion.

But be careful:

13F reported value
≠ total assets under management

A manager may hold assets and exposures outside the Section 13(f) reporting universe.

Treat the summary as the size of the reported 13F portfolio, not necessarily the manager's complete portfolio.

The information table is where the reported securities appear.

Current Form 13F instructions include columns for:

• Name of Issuer;
• Title of Class;
• CUSIP and optional FIGI;
• Market Value;
• Shares or Principal Amount;
• Put/Call designation where applicable;
• Investment Discretion;
• Other Manager;
• Voting Authority.

For most investment research, you will spend most of your time on:

Issuer
Security class
Reported value
Shares
Put/Call

The other fields can still matter, but these are usually the most useful starting point for portfolio analysis.

A position's reported market value can change even when the manager does not trade.

Suppose:

Q1 shares:
1,000,000

Q2 shares:
1,000,000

The manager reported the same share count.

But if the stock price rises 40%, the reported market value can rise substantially.

If you looked only at value, you might incorrectly conclude that the manager increased the position.

For quarter-over-quarter activity, start with:

Reported shares

Then look at:

Reported market value

The first tells you more directly whether the reported quantity changed.

The second tells you how large the position was in value terms at the reporting date.

Suppose:

Previous quarter:
2,000,000 shares

Current quarter:
2,500,000 shares

The percentage change is:

(2,500,000 − 2,000,000)
÷ 2,000,000
× 100

= 25%

You can describe this as:

> Reported shares increased 25% quarter over quarter.

That wording is more precise than:

> The manager bought 25% more.

Why?

Because the filings show two quarter-end snapshots. They do not show the exact timing or sequence of trades between those dates.

When comparing two consecutive filings, positions can often be grouped into a few useful categories.

New

Previous quarter:
No active reported position

Current quarter:
Shares > 0

Interpretation:

> The position appears as a new reported holding relative to the previous comparable filing.

Do not interpret this as the exact day the position was opened.

Increased

Current shares > Previous shares

Interpretation:

> The manager reported more shares at the current quarter-end.

Unchanged

Current shares = Previous shares

Interpretation:

> The reported share count did not change between the two quarter-end snapshots.

Reduced

0 < Current shares < Previous shares

Interpretation:

> The manager reported fewer shares at the current quarter-end.

Exited / Sold Out

Previous shares > 0
Current active reported shares = 0

Interpretation:

> A previously reported position no longer appears as an active reported holding in the current comparable filing.

These labels are useful shorthand, but they are still based on filing snapshots.

A useful derived metric is the position's weight within the reported 13F portfolio.

Formula:

Reported portfolio weight
= Position reported value
  ÷ Total reported 13F value
  × 100

Example:

Position value = $3 billion
Total reported 13F value = $30 billion

Then:

Portfolio weight
= $3B ÷ $30B × 100
= 10%

That makes the position a 10% holding within the reported 13F portfolio used in the calculation.

It does not necessarily mean:

> 10% of the manager's total assets.

The distinction is important.

This is where 13F analysis becomes more informative.

Suppose:

Shares:
+20%

Portfolio weight:
+0.5 percentage points

The manager reported more shares, and the position also became slightly more important in the reported portfolio.

Now consider:

Shares:
+20%

Portfolio weight:
-1.0 percentage point

The manager still reported more shares, but the position became a smaller share of the reported portfolio.

Possible reasons include:

• other holdings rose more;
• other positions were added;
• total reported portfolio value increased;
• the stock underperformed other holdings.

This is why a single metric rarely tells the whole story.

One of the fastest ways to understand a manager is to sort the filing by portfolio weight.

Look for:

Top 1
Top 5
Top 10

Ask:

• How concentrated is the portfolio?
• Does one stock dominate?
• Do the top five positions account for a large share of reported value?
• Has concentration increased or decreased?

A manager with:

Top 5 = 70%

has a very different reported portfolio structure from one where:

Top 5 = 20%

Concentration often tells you more about the portfolio than the total number of reported holdings.

A very large percentage can come from a tiny starting position.

Suppose:

Previous quarter:
1,000 shares

Current quarter:
5,000 shares

Percentage increase:

+400%

That sounds dramatic.

But the position may still be economically insignificant.

Compare that with:

Previous quarter:
10,000,000 shares

Current quarter:
12,000,000 shares

Percentage increase:

+20%

The percentage is smaller, but the absolute increase is:

2,000,000 shares

and the dollar significance may be much larger.

Always read:

Percentage change
+
Absolute share change
+
Current position size

together.

Suppose a filing reports:

Shares:
1,000,000

Reported value:
$180,000,000

Dividing gives:

$180 per share

That may approximate the quarter-end value implied by the filing.

It does not mean the manager bought the position at $180.

The manager could have accumulated the position:

• over multiple quarters;
• at many prices;
• in multiple accounts;
• through many individual transactions.

A 13F does not disclose a reliable average purchase cost.

Form 13F can include certain reportable put and call option positions.

If an entry contains a Put/Call designation, do not analyze it as if it were ordinary common stock.

A reported option position can have a very different economic meaning from a long equity holding.

For example, a put position may relate to:

• hedging;
• downside protection;
• a directional view;
• a broader options structure.

The 13F alone may not reveal the complete strategy.

So if you see:

PUT

or:

CALL

separate that entry from ordinary share ownership in your interpretation.

A reported long position does not necessarily tell you a manager's net exposure.

For example, the filing may show a long equity holding, while the manager also has:

• short exposure elsewhere;
• derivatives;
• index hedges;
• sector hedges;
• other non-13F positions.

This is especially important when analyzing hedge funds.

A 13F can show part of the portfolio without showing the strategy that surrounds it.

One quarter can be noisy.

Three or four quarters can reveal a pattern.

Suppose:

Q1:
1.0 million shares

Q2:
1.4 million shares

Q3:
1.9 million shares

Q4:
2.3 million shares

That is a more meaningful multi-quarter accumulation pattern than a single one-quarter increase.

Likewise:

Q1:
5.0 million

Q2:
4.5 million

Q3:
3.1 million

Q4:
1.2 million

suggests repeated reductions in reported shares.

A trend does not tell you what happens next, but it gives more context than one isolated filing.

A filing can tell you:

Reported shares increased 35%

It cannot tell you with certainty:

The manager believes the stock is 35% more attractive.

Portfolio changes can happen for many reasons.

Possible explanations include:

• new investment conviction;
• rebalancing;
• client subscriptions or withdrawals;
• merger-arbitrage activity;
• risk-budget changes;
• mandate changes;
• tax management;
• a hedge elsewhere in the portfolio.

The filing shows what changed.

It rarely proves why.

A powerful way to use 13F data is to start from a stock instead of a manager.

For a stock such as Company X, ask:

• How many tracked managers reported it?
• Which managers have the largest reported positions?
• Who added shares?
• Who reduced shares?
• Who reported a new position?
• Who no longer reported the position?
• Is ownership concentrated among a few managers?
• Is the direction of change consistent or mixed?

This can reveal whether institutional activity is broad or concentrated.

You can explore this directly through the BasisPilot 13F Holdings Tracker, which organizes 13F data by both manager and stock.

Suppose a manager reports the following:

Previous quarter:
Shares = 4,000,000
Reported value = $320 million
Portfolio weight = 4.0%

Current quarter:
Shares = 5,000,000
Reported value = $500 million
Portfolio weight = 4.4%

Share Change

(5,000,000 − 4,000,000)
÷ 4,000,000
× 100

= +25%

The manager reported 25% more shares.

Market Value Change

$500M − $320M
= +$180M

But not all of that $180 million necessarily came from buying.

Part may reflect the stock price increasing.

Weight Change

4.4% − 4.0%
= +0.4 percentage points

The position also became slightly larger relative to the reported portfolio.

A careful summary would be:

> The manager reported 5.0 million shares at the current quarter-end, up 25% from 4.0 million in the prior comparable filing. The position represented 4.4% of the reported 13F portfolio, up from 4.0%.

That is stronger than saying:

> The manager made a huge bullish bet.

The first statement is supported by the filing comparison.

The second adds an interpretation the filing cannot prove on its own.

Suppose:

Previous:
2,000,000 shares
$200 million value

Current:
2,000,000 shares
$280 million value

Shares:

0% change

Reported value:

+40%

This does not indicate an increase in reported share count.

The higher market value may simply reflect a higher security price at quarter-end.

This is why scanning only the "value" column can be misleading.

Suppose:

Previous:
1,000,000 shares
Portfolio weight = 6%

Current:
1,200,000 shares
Portfolio weight = 5%

The manager reported:

+20% shares

but the position's portfolio weight fell by:

-1 percentage point

Possible explanation:

The rest of the reported portfolio grew faster than this position.

Again, the two numbers answer different questions.

Suppose:

Q1:
No reported position

Q2:
3,000,000 shares

A tracker may label it:

New

That means the position is new relative to the previous comparable quarter-end filing.

It could have been purchased early in Q2.

It could have been purchased late in Q2.

By the time the Q2 filing is public, the position could already have changed.

"New" is a historical comparison label—not a real-time alert.

Suppose:

Q1:
1,500,000 shares

Q2:
No active reported position

You can reasonably say:

> The position no longer appeared as an active reported holding in the Q2 filing.

You cannot infer:

• the exact sale date;
• the sale price;
• whether it was sold in one trade;
• whether the manager later reopened the position after quarter-end.

The filing shows the endpoint, not the complete trading path.

Raw SEC filings are essential primary-source records, but quarter-over-quarter comparison becomes cumbersome when a manager has hundreds of positions.

The BasisPilot 13F Holdings Tracker is designed to make the comparison layer easier to read.

You can use it to review:

• manager holdings;
• stock-level institutional ownership;
• reported shares;
• reported market value;
• portfolio weight;
• quarter-over-quarter changes;
• new positions;
• increased positions;
• reduced positions;
• reported exits.

Use the tool for comparison and discovery, then go back to the underlying SEC filing when you need to verify the primary record.

If you do not want to analyze every line, use this faster process.

Minute 1: Confirm the Dates

Check:

Period of Report
Filing Date

Minute 2: Confirm the Filer

Check the legal manager name and report type.

Minutes 3–4: Scan Concentration

Look at:

Top 5 positions
Top 10 positions
Largest portfolio weights

Minutes 5–6: Find the Biggest Share Changes

Separate:

New
Increased
Reduced
Exited

Minute 7: Check Absolute Size

Ignore dramatic percentages on tiny positions unless they become economically meaningful.

Minute 8: Compare Shares vs Value

Ask whether the change came from reported quantity, market price, or both.

Minute 9: Look Across Previous Quarters

Determine whether the change is part of a trend or a one-quarter event.

Minute 10: Write Only What the Filing Supports

Prefer:

> Reported shares increased 25%.

over:

> The manager is extremely bullish.

This one habit improves 13F analysis immediately.

Mistake 1: Treating the Filing Date as the Holdings Date

Wrong:

> The manager owned this on August 14 because the filing is dated August 14.

Better:

> The filing submitted on August 14 reports holdings as of the quarter-end date.

Mistake 2: Treating Reported Value as Purchase Cost

Wrong:

> The fund's average entry price was $180.

Better:

> The filing implies approximately $180 per share in reported quarter-end value.

Mistake 3: Treating "New" as a Current Buy Signal

Wrong:

> The manager just bought this stock.

Better:

> The position newly appeared in the current quarter-end filing relative to the prior comparable filing.

Mistake 4: Reading Only Percentage Change

A 500% increase in a tiny position may matter less than a 10% increase in a top holding.

Mistake 5: Ignoring Portfolio Weight

Share changes are more useful when you also understand how important the position is within the reported portfolio.

Mistake 6: Assuming 13F Equals the Complete Portfolio

It does not.

Mistake 7: Ignoring Amendments

An amended filing can change the historical comparison.

Mistake 8: Assuming the Manager Still Holds the Position

The filing is delayed.

Before using a 13F position in your research, check:

• What is the period of report?
• What is the filing date?
• Is this an original filing or an amendment?
• What is the legal manager name?
• What is the report type?
• How many total entries are reported?
• What is the total reported 13F value?
• How many shares are reported for this security?
• What was the prior quarter's share count?
• Is the position new, increased, unchanged, reduced, or exited?
• What is the absolute share change?
• What is the percentage share change?
• What is the reported market value?
• What is the position's reported portfolio weight?
• Did the weight change because of shares, price, or broader portfolio changes?
• Is the entry common stock or an option?
• Is there an amendment that supersedes the filing?
• What do the previous three or four quarters show?
• Am I accidentally treating historical data as current?
• Am I making a claim the filing itself cannot prove?

If you can answer those questions, you can read most 13F filings with much more precision.

Where do I find the shares in a 13F?

The information table includes the reported shares or principal amount for each entry.

For ordinary stock holdings, the share count is one of the most useful fields for quarter-over-quarter comparisons.

What is the most important number in a 13F?

There is no single best number.

For position-change analysis, reported shares are especially useful.

For portfolio importance, reported value and derived portfolio weight matter.

The strongest analysis combines them.

How do I know whether a fund bought or sold a stock?

Compare reported share counts between consecutive quarter-end filings.

If current shares are higher, the reported position increased.

If lower, it decreased.

But the filing does not show the exact trade dates or individual executions.

How do I calculate percentage change in a 13F position?

Use:

(Current shares − Previous shares)
÷ Previous shares
× 100

How do I calculate 13F portfolio weight?

Use:

Position reported value
÷ Total reported 13F value
× 100

Does a higher market value mean the manager bought more?

Not necessarily.

The stock price may simply have risen.

Check the share count.

Can I calculate a manager's average purchase price from a 13F?

Not reliably.

The filing reports quarter-end holdings and market value, not the actual cost basis.

What does 13F-HR/A mean?

It is an amended Form 13F holdings report.

Review the amendment rather than assuming the original filing remains the final version.

What does "new position" mean?

It usually means a position appears in the current comparable filing but not in the previous comparable filing.

It does not reveal the exact purchase date.

What does "sold out" mean?

It generally means a previously reported active position no longer appears as an active position in the current comparable filing.

Should I copy trades from 13F filings?

A 13F is better used as a research input than as a real-time trade alert.

The data is delayed and does not show the manager's complete portfolio or exact rationale.

Reading a 13F well is mostly about separating what the filing actually says from what you might be tempted to infer.

A disciplined process looks like this:

Quarter-end date
→ Filing date
→ Manager
→ Filing type
→ Shares
→ Reported value
→ Portfolio weight
→ Quarter-over-quarter change
→ Multi-quarter trend
→ Limitations

The filing can show that a reported position changed.

It usually cannot tell you exactly when the trade happened, what price the manager paid, why the manager made the change, or whether the same position still exists today.

Use 13F data to study institutional portfolio structure and historical changes—not as a substitute for real-time holdings or complete portfolio information.