Micro-cap investing

Ian Cassel has picked micro caps for more than twenty years, founded MicroCapClub, and runs a fund that does nothing else. His book Stock Picker: How to develop the mindset, temperament, and strategy to outperform Wall Street (Harriman House, September 2026) is the most useful account of the corner of the market where the rest of the value canon says the least. This essay is what it changes about our process, and what it leaves alone. The scoring, the fair value, the margin of safety and the kill criteria all apply. The weights move.

What is a micro-cap stock, and why would a value investor bother?

A micro cap is a listed company with a market value under roughly $300 million; some definitions stretch to $500 million. There are thousands of them in the United States and Canada alone, and almost none are owned by institutions, because a fund that must deploy billions cannot buy a $100 million company without becoming its largest holder. That exclusion is about liquidity, not quality, and it is the whole opportunity. The research Ian Cassel cites in Stock Picker found that 87% of the stocks that returned ten times or more over the past decade started as micro caps, and 91% of those were already profitable when the run began. The catch is the base rate: most micro caps lose money and stay small. The job is to find the profitable minority before anyone with a research budget does.

The exclusion is structural, which is why it persists. A fund with $2 billion under management cannot own a meaningful position in a $80 million company: it would take a quarter of the float, need a year to build it, and never be able to sell. So the fund does not look, the sell side does not cover, and the stock trades on whoever happens to have read the filings. An individual investor with a few hundred thousand to deploy has no such constraint. That is the whole edge, and it is one of the few that the market cannot arbitrage away.

How is micro-cap investing different from large-cap value investing?

The process is the same: understand the business, value it, buy with a margin of safety, write down what would make you wrong. Three things change. Management matters far more, because a $150 million company is one or two people and their decisions; you analyse it the way an angel investor analyses a founder, and you can actually talk to them. Capital is scarce, so dilution and debt replace competition as the biggest risk. And the stock has a life cycle of its own: it gets discovered, then it has to prove itself, and the price does very different things in each phase.

A large cap has a moat you can measure: switching costs in the renewal rate, brand in the gross margin, scale in the cost per unit. A micro cap usually has a moat it is still digging, and the person holding the shovel is the investment. That is why Cassel says to analyse the company like an angel investor: the questions are about the operator before they are about the operation. Can this person execute? Have they already executed something? Is their money in the stock beside yours? On the Invest Board company page, management is one of the six scored pillars for every company. In micro caps it is the first one to read.

What are the discovery move and the fundamental move?

A micro cap that works tends to move twice. The first move is discovery: a story gets told, a few investors find the stock, and the price rises on attention rather than earnings. The second move is fundamental: the company executes, revenue and free cash flow arrive, and the price follows the numbers. Cassel borrows Pierre Lassonde’s curve from junior mining to describe the gap between the two, a long trough where the story is old news and the results are not yet in. The best entry is before discovery. The most dangerous moment is the top of the discovery spike, when the stock is priced for perfection and nothing has been proven. If the story survives the trough and the fundamentals show up without new shares being printed, the second move is the one worth owning.

The ownership base tells you where in the cycle a stock sits. Before discovery it is held by retail investors who did the reading. During discovery small institutions arrive, then larger ones as the market cap and the liquidity grow into their mandates. At the top, late retail buys from the funds. When risk comes off, the institutions sell first and fastest, which is why a micro cap without institutional holders can fall less in a panic than a small cap that has just graduated into a fund’s universe. Themes and trends pull stocks through the discovery move; only execution carries them through the fundamental one.

How do you judge management in a micro cap?

Look for what Cassel calls an intelligent fanatic: an owner-operator who is all in, thinks in decades, refuses the status quo, and has already executed at least part of what they said they would do. The checklist is concrete. Insider ownership that means something to the person holding it. A capital allocation record you can read in the filings: no dilution without a return, no debt for its own sake, buybacks only when cheap. A flat organisation where ideas travel. A simple story you can repeat in two sentences. Story stocks need a leader who can deliver; the difference between a Jobs or a Musk and a promoter is the delivered part. If you can visit, visit. Inspect the product, the service, the assets. Stay close enough to notice when the story changes.

The template is William Thorndike’s The Outsiders: operators who redefined their industries by allocating capital like owners rather than managers. The micro-cap version is earlier and rawer. The founder is often still the largest shareholder, the board is small, and there is no bench. That concentration cuts both ways. When it works, every decision is made by the one person with the most to lose. When it fails, there is nobody to stop them. The insider transactions on the company page, with the ninety-day net figure, are the first place to look: an owner buying in the open market in an illiquid name is a rare and honest signal.

Why is dilution the biggest risk in micro caps?

Because a company that needs capital will get it from you. Every raise at a low price transfers part of the business from existing holders to new ones, and a company that raises repeatedly is compounding against its own shareholders. The rule is blunt: if they need money, stay away. Prefer organic growth funded by positive free cash flow, a balance sheet with little or no debt, and a share count that barely moves from year to year. Bull markets read the income statement and reward growth; bear markets read the balance sheet and punish debt. A micro cap with cash and no need to raise survives the second kind of market and buys competitors in it.

The test is simple to run. Read three years of balance sheets and count the shares. If the share count grows faster than the business, the shareholders are paying for the growth. Then look at cash against the annual burn or the annual free cash flow. A company with a year of runway and no profits will raise within the year, and the price of that raise is set by the market on the company’s worst day, not yours. This is where the small-cap balance sheet reading in our Value tab does the work; the numbers are the same, only the consequence is larger.

How do you find micro-cap ideas when screens do not work?

Quantitative screens miss most micro-cap winners because the company is not perfect yet: margins are low, the history is short, the numbers that will eventually screen well do not exist. What works is narrower. An event screen on market cap and revenue finds small businesses with real sales. Insider buying is one of the few signals that transfers cleanly, since an owner buying with their own money in an illiquid stock is not doing it for show. Researching a sector end to end surfaces the small names beside the large ones. Other micro-cap investors are a better source than any database. Expect two good ideas a year, and do not buy until you have found one.

Two ideas a year sounds like too few until you count what an idea costs: the filings, the calls, the visit, the reference checks with customers and former employees, the months of watching before the first purchase. Cassel’s phrase for the result is conviction, and his definition is doing the work more than anyone else. The screener in Invest Board carries a three-month insider net buying filter for exactly the one signal that survives at this size; the rest of the sourcing is reading and people. Peter Thiel’s test from Zero to One applies with unusual force here: the best small company dominates a market small enough that nobody large wants it yet.

How do you value a micro cap?

Conservatively, and with the downside first. A useful bar is that the business should be able to double in three years without any expansion of the multiple, which needs earnings or free cash flow growing around 25% a year from the current price. If the case requires a re-rating to work, it is a speculation on other people’s opinion. Prefer the misunderstood, the undiscovered and the unappreciated, the uncrowded trade before institutions can own it. Scarcity plus a tailwind is how a micro cap becomes overvalued; both together are a reason to check the price twice. A boring business in a niche it dominates, growing without raising money, is the shape most of the survivors share.

The double-in-three-years bar does the same job as our margin of safety, from the other direction. Instead of asking what the business is worth and buying at half, it asks what the business must do for the purchase to work without help from the crowd. If the answer is a growth rate the company has already shown, in a niche it already leads, with cash it already has, the entry price is probably right. If the answer needs a new product, a new market and a new multiple, it is three bets dressed as one. Think about the downside more than the upside: the company that cannot go to zero is the one you can size.

When do you sell a micro cap?

Ask the only question that matters: would I buy this stock today at this price? Three answers justify a sale. The price has run far past any fair value you can defend. You have found something clearly better. The story has changed. A falling price on its own is none of those. If the drop is not about the business, it is a chance to buy more; if it is about the business, it is a reason to sell. A stock that falls by half and does not tempt you to add is a stock you did not understand in the first place. Micro-cap prices are bumpy by nature, so the discipline is to watch the fundamentals and the story, not the tape.

The discovery spike is the tempting exception. A stock that has tripled on a story, with institutions arriving and the multiple priced for perfection, meets the first sale test even if the business is fine. Cassel’s pattern is to sell into that, and to buy again when the story has gone stale and the fundamentals are still compounding. It is the one place in value investing where selling something you like is the disciplined act. The kill criteria on the Decide tab hold the story version of the same rule: write down what would change your mind before you buy, so a changed story is a fact you recorded rather than a feeling you rationalise.

What temperament does micro-cap investing require?

Patience in both directions. Waiting for the right idea, then waiting while the company does the work. Concentration, because two good ideas a year cannot fill a fifty-stock portfolio. The willingness to average up when management and the business keep delivering, and to let winners run past the point where they feel large. Buying in bear markets, when the best investors are throwing in the towel and the bottom is near. Conviction that comes from having done more work than anyone else on the name, so that a bad quarter reads as noise and a changed story reads as a signal. Sitting is working.

Fear and greed run stronger at the small end because the prices move more and the news flow is thinner. A micro cap can fall 40% on no news and rise 60% on a contract. Worrying about the next quarter is a sign that the position is too large for the conviction behind it, or that the work was never done. The cure is a three-year horizon with a few key metrics tracked on a schedule, and an investment journal that records what you believed on the day you bought. When the price moves, you read the journal before the chart.

What carries over, and what to change

The process in Invest Board is built for the value investor at any size: the six-pillar score, fair value with a margin of safety, the thesis in three lines, the kill criteria, the journal. For micro caps, read them in a different order. Management first, then the balance sheet and the share count, then the story and where it sits on the discovery curve, and only then the valuation. Add two questions the page cannot answer for you: have I talked to the people running this, and would I buy more if it fell by half. Every feature is one plan at $5 a month after a 30-day trial, which is less than the cost of a single annual report printed and bound.

General investment analysis · not personalized advice.