Investing · case studies

How professionals think, from what they published.

5 studies of ideas that are on the public record: what was said, where it was published, an example with its dates, a failure, and what a private account cannot reproduce. They explain a way of reasoning. They do not say what to buy.

What filings show The five studies

Read this first

No endorsement and no connection.: GIO4X has no connection with any person or firm named on these pages. None of them has seen, approved or endorsed anything here.
Nobody here sees their portfolios.: These pages are written from books, letters and papers that anyone can read. Nobody at GIO4X has access to the holdings, the orders or the records of the people named.
A method is not its results.: Studying how someone reasoned does not reproduce what they earned. Their results came from particular decisions in particular years, made with resources a private account does not have.
A leveraged CFD is not an investment held.: A contract for difference gives no ownership of a share, a fund or a bond. It is a leveraged agreement on a change in price, and it does not behave like the holdings these studies describe.

Before the studies

What public disclosure shows, and what it does not.

In several countries large investment managers must publish periodic reports of some of their holdings. These reports are the basis of every list of “what the famous investors own”. It is worth knowing what kind of document they are before reading anything into one.

What a holdings report shows

Certain holdings, on one day: A holdings report is a list of some of what a large manager held at the end of a period, often a quarter. It is a photograph of one date.
Names and amounts: For each holding it usually gives the security and the quantity or value on that date.
Changes between two photographs: Comparing one report with the last shows what was larger or smaller at the two dates. It does not show what happened between them.

What it does not show

It is late: Reports are published some weeks after the date they describe. By the time one can be read, the holding may have been added to, reduced or sold. A reader learns of a sale only from the next report, a further period on.
It is incomplete: Reports of this kind typically cover long positions in certain listed securities. They commonly leave out short positions, many derivatives, cash, and holdings outside the reporting rules, such as assets in other countries, bonds, currencies, commodities and private investments.
It gives no reason: A holding may be a view on the company, half of a pair with something that is not shown, a hedge against something else, or the remains of an older position being sold down. The report does not say.
It gives no price: The report does not show when the holding was bought or what was paid. A copier pays the price on the day he or she reads it, which may be very different.
It does not say whose decision it was: A filing is made by a firm. It may combine the decisions of several managers and several portfolios with different aims.
It may be held back: In some systems a manager can ask for a holding to be withheld from the public report for a time, for example while a position is still being built.
It shows none of the conditions: The financing behind a position, its tax treatment, the size of the whole portfolio around it and the time the holder can wait are all invisible, and none of them transfers to a copier.

So “copying” is not what it sounds like

Someone who buys what a filing lists is buying weeks or months after the original holder, at a different price, a part of a position whose other parts are not visible, for a reason that was never given. If the original holder has since sold, the copier finds out a further period later, from the next report.

The copier also holds it under different conditions: without the same financing, without the same tax position, and without the ability to wait that the original holder may have. The same holding in two different accounts is not the same investment.

This describes holdings reports in general. The detailed rules, including who must report, what and how soon, differ from country to country and change over time; the regulator of each market publishes them.

The studies

Five ways of thinking, one page each.

Four are about people whose ideas are in print under their own names. The fifth is about the process inside large institutions, and names no firm.

How a study is built

The same six parts every time.

The aim is to be checkable. A reader should be able to find the source, read it and disagree with the summary.

The ideas, with their sources: Each idea is paraphrased and tied to the book, letter or paper it comes from, named by title, author, publisher and year. There are no quotations and no links.
A documented example: One episode from the public record, told with its dates. A figure appears only where it is well known and comes from the named source.
A failure the record admits: Every study includes what went wrong, in most cases in the person’s own account. A method described only by its successes has not been described.
A paper exercise: What part of the thinking can be practised with a hypothetical portfolio, linked to a tool that already exists on this site.
What does not scale down: The financing, access, staff, tax position and time horizon behind the original, none of which a private account has.
One idea to handle: An interactive sketch of the idea itself on invented figures: a margin, a cost, four environments, a loop, a sliced order. Never a record of anyone’s results.

Questions people ask

Can I copy a famous investor’s portfolio from public filings?: Not in the sense the phrase suggests. Holdings reports are published weeks after the date they describe, cover only certain kinds of holding, and usually leave out short positions, many derivatives and assets outside the reporting rules. They give neither the price paid nor the reason for the holding. A copier buys later, at a different price, without knowing whether the position still exists.
Are these case studies endorsed by the investors named?: No. GIO4X has no connection with any person or firm named, and none of them has seen or approved these pages. The studies are written from books, shareholder letters, papers and official reports that anyone can read, and nobody at GIO4X has access to anyone’s portfolio.
Will studying a professional investor’s method produce the same results?: No. A method is a way of reasoning; a result came from particular decisions in particular years, made with financing, access, staff, tax treatment and a time horizon that a private account does not have. Each study lists what does not scale down, and each includes a failure, because the same method also produced losses.

Summaries for study, in this site’s own words, of ideas that are on the public record. They are not endorsed by, or connected with, anyone named, and nobody at GIO4X has access to their portfolios. Studying a method does not reproduce its results, and a leveraged CFD is not ownership of an investment and does not behave like one. Educational information, not investment advice or a recommendation to trade.

The value of any investment can fall as well as rise, and an investor can get back less than was put in. Past results, of anyone, say nothing certain about future ones.

Trading foreign exchange on margin carries a high level of risk, and may not be suitable for all investors. The high degree of leverage can work against you as well as for you. Before deciding to trade foreign exchange you should carefully consider your investment objectives, level of experience, and risk appetite. The possibility exists that you could sustain a loss of some or all of your initial investment and therefore you should not invest money that you cannot afford to lose.

Continue

Fetching the page

What public disclosure shows, and what it does not.

What a holdings report shows

Certain holdings, on one day: A holdings report is a list of some of what a large manager held at the end of a period, often a quarter. It is a photograph of one date.
Names and amounts: For each holding it usually gives the security and the quantity or value on that date.
Changes between two photographs: Comparing one report with the last shows what was larger or smaller at the two dates. It does not show what happened between them.

What it does not show

It is late: Reports are published some weeks after the date they describe. By the time one can be read, the holding may have been added to, reduced or sold. A reader learns of a sale only from the next report, a further period on.
It is incomplete: Reports of this kind typically cover long positions in certain listed securities. They commonly leave out short positions, many derivatives, cash, and holdings outside the reporting rules, such as assets in other countries, bonds, currencies, commodities and private investments.
It gives no reason: A holding may be a view on the company, half of a pair with something that is not shown, a hedge against something else, or the remains of an older position being sold down. The report does not say.
It gives no price: The report does not show when the holding was bought or what was paid. A copier pays the price on the day he or she reads it, which may be very different.
It does not say whose decision it was: A filing is made by a firm. It may combine the decisions of several managers and several portfolios with different aims.
It may be held back: In some systems a manager can ask for a holding to be withheld from the public report for a time, for example while a position is still being built.
It shows none of the conditions: The financing behind a position, its tax treatment, the size of the whole portfolio around it and the time the holder can wait are all invisible, and none of them transfers to a copier.

So “copying” is not what it sounds like

Questions people ask

Can I copy a famous investor’s portfolio from public filings?

Not in the sense the phrase suggests. Holdings reports are published weeks after the date they describe, cover only certain kinds of holding, and usually leave out short positions, many derivatives and assets outside the reporting rules. They give neither the price paid nor the reason for the holding. A copier buys later, at a different price, without knowing whether the position still exists.

Are these case studies endorsed by the investors named?

No. GIO4X has no connection with any person or firm named, and none of them has seen or approved these pages. The studies are written from books, shareholder letters, papers and official reports that anyone can read, and nobody at GIO4X has access to anyone’s portfolio.

Will studying a professional investor’s method produce the same results?

No. A method is a way of reasoning; a result came from particular decisions in particular years, made with financing, access, staff, tax treatment and a time horizon that a private account does not have. Each study lists what does not scale down, and each includes a failure, because the same method also produced losses.