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Why a great business can still lose you money

A company reports record profits and its shares go nowhere for years. That is not a conspiracy or a mistake. It is multiplication, and it takes two minutes to understand for good.

The whole thing in one line

A share price is not a measure of how well a company is doing. It is two separate things multiplied together:

What a share price actually is

Share price=earnings per share ×the multiple

Earnings per share: What the business earned, divided by the shares in issue. This is the company's doing.
The multiple: How many years of those earnings buyers will pay for today. This is not the company's doing at all — it can halve in a year with nothing changing inside the business.

Earnings up × multiple down further = share price down, with nothing wrong at the company

The share price is these two multiplied together — so it has two ways to move, and only one of them is about the business. A company can earn more every single year while buyers steadily decide to pay less for each dollar it earns. If the blue line falls by more than the amber line rises, the price falls. That is arithmetic, not misfortune.

The same thing, actually happening

IDEXX Laboratories passes every structural test in our Exceptional Company Series. Measured from its July 2021 high to August 2026, nothing was wrong with the business — it was one of the best stretches in its history.

	July 2021	August 2026	Change
Earnings per share	$7.52	$13.58	×1.81 (+81%)
The multiple paid for them	90×	41×	×0.45 (−55%)
Share price	$679	$557	×0.82 (−18%)

Read the last column as multiplication: 1.81 × 0.455 = 0.82. Earnings nearly doubled; buyers decided to pay less than half as much for each dollar of them. The second effect was bigger, so the shareholder lost money — for 52 months.

Earnings +81% × multiple −55% = price −18% over five years

Everything indexed to 100 at July 2021. The business went one way and the market's opinion of it went the other, and the price — being the two multiplied together — spent five years going roughly nowhere.

The only unusual thing here is the starting multiple of 90×, a price that already assumed years of excellent results. When they arrived, they had already been paid for.

Two things worth knowing

Why multiples move: Mostly two reasons, neither involving the company: how much growth buyers expect afterwards, and what else they could do with the money. When interest rates rise, a bond starts paying a real return and every share competes with it, so buyers pay less for the same earnings. That appears instantly in the price and never in the results.
It works in reverse, and that one is more dangerous: A mediocre business whose multiple expands from 12× to 24× doubles its share price having earned nothing extra. Its holders will conclude they picked well. They were paid by a change of mood, which cannot be researched or repeated, and can be handed back as fast as it arrived.

Then why write about businesses at all?

If this is not a recommendation, and a company here might still lose you money for years, what is the work for?

1: The two questions only work in this order. You cannot judge a price until you know what is being priced.
2: Only the first one keeps. Understanding a business takes weeks and stays true for years; a multiple changes in a month.
3: It is what lets you act when the price finally moves. The de-rating above was a company becoming available at half the price to anyone who already understood it — and a frightening chart attached to a stranger, for anyone who did not.

So: exceptional can also be expensive. A wonderful business is a necessary condition for a good long-term investment, and not remotely a sufficient one. Settling the durable half in advance is the point of the series. It is a watchlist built on evidence, not a list of things to buy today.

Terms used here are defined in Key terms. Figures: IDEXX Laboratories (IDXX), month-end closing prices and trailing twelve-month earnings as announced, from our own store, as at August 2026. General explanation, not personal advice, and not a recommendation to buy or sell anything. Capital is at risk.