The following list is not exhaustive, but experience shows that the vast majority of listed companies fall into one of these six categories. Sometimes, they move from one to another as they evolve; sometimes, they are a composite of two or more categories.

First category: the venerable. Reputable, well-managed, well-established, even the leader in its sector, it generally boasts a solid competitive advantage due to its scale, and defends a double-digit return on equity without excessive leverage. As such, profits and dividends grow slowly and steadily, without major hitches.

Seized at attractive valuation multiples, for example during a recession or a temporary disruption in its sector of activity, it represents the defensive investment par excellence - which doesn't make it any less of an opportunity. This is the category in which enterprising investors most often begin their journey.

Second category: good payers. They too are mature, but have reached a glass ceiling or structural limit that nullifies their growth prospects and severely compresses their profitability. This is where it differs from the venerable one.

Because its prospects are blocked, value creation - see ABC of financial analysis: value creation vs. value destruction - is now limited to the dividends it will be able to distribute to its shareholders. The market treats it as such, in other words, as a kind of junior bond.

Third category: cyclicals. Subject, as its title suggests, to violent economic downturns, it operates in a difficult, capital-intensive and competitive sector, often with a high fixed-cost structure and a high level of debt. Its profitability can be off the charts one year, for example because of a sudden imbalance in supply and demand, and cataclysmic the next.

Cyclicality is a short-term investment - a speculation - that can sometimes be quite brilliant, particularly when you manage to catch the low point, that is, the moment that precedes the rebound but follows the complete desertion of other investors, disgusted by their losses. It's a maximum-risk situation when, on the contrary, you enter at the top, in the midst of euphoria, extrapolating an unsustainable trend.

Fourth category: the serial buyer. The latter is driven by M&A - mergers and acquisitions - to ensure growth, which is then described as "external". They sprout like mushrooms during bubble periods or stock market euphoria. On the other hand, they drop like flies - only to be bought up for a pittance or sold off - during recessions.

These "serial acquirers" are often led by charismatic managers, skilled promoters capable of raising capital at a sustained pace and on preferential terms. Their talents enable them to finance all-out aggregation strategies... for better or for worse. Clearly, their strategy makes sense when returns on investment are good, just as it threatens to collapse like a house of cards when they are precarious or uncertain.

Fifth category: the special situation. It may belong to each of the above categories, or even embody a curious mixture of the two. What makes it special is that an activist investor or management has taken over the company, with the intention of restructuring it in depth.

In most cases, the idea is to sell off as many so-called "non-strategic" assets as possible, in order to restore solvency and try to make a hidden crown jewel shine. Difficult to assess, these situations are reserved for sophisticated investors, ideally familiar with the highly complex governance dynamics around which the reorganization strategy is built.

Sixth category: fraud. An experienced eye will learn to recognize them at a glance, or almost at a glance. Under cover of grandiose promises, the listed company in question lives off its investors and lies to them shamelessly; in reality, it is a vehicle for transferring wealth from their pockets to those of its promoters.

Its hallmarks are almost always the same: operational activity that is difficult to understand or discern; financial communication that is as opaque as it is built around wild promises; a management team with a shady, or at any rate unverifiable, pedigree, but with excessive remuneration, thanks in part to the distribution of stock options.