Your stock’s moat is probably shrinking: how to read moat trend before the market does

Once you can spot an economic moat, the temptation is to sort companies into “wide” and “narrow” and call it done. Wide feels safe. But moat width is a snapshot of a company’s defenses today, and a snapshot is a lagging indicator. Pat Dorsey, who built Morningstar’s moat-rating system, makes the sharper point in his book on moats: the durability of an advantage matters far more than its current level. So the question that actually decides your decade isn’t how wide the moat is. It’s which way it’s moving.

Here is the claim, stated plainly. A narrow moat that is widening will out-compound a wide moat that is eroding, given a long enough hold. The width tells you where the business stands; the trend(whether the defenses are thickening, holding, or being stormed) tells you where it’s headed. Most investors read the first number and ignore the second. That gap is the opportunity.

Width is a lagging indicator

Consider Kodak. By the mid-2000s its film franchise was visibly under siege, yet the surface numbers still flattered it. In 2005 Kodak topped the U.S. digital-camera market with roughly 21% share and grew that revenue line about 40% in a year. On a market-share basis the moat looked intact. Underneath, the business was selling cameras at a loss of around $60 apiece into a category with thin margins and almost no barriers to entry. The width reading said “leader.” The trend had already turned years earlier, when an outside technology quietly changed what a customer actually needed. Kodak filed for bankruptcy in 2012. The investor watching only the width rating sold near the trough; the one watching the trend had a reason to leave near the peak.

Now run it the other way. Amazon in the early 2000s looked, on any static measure, like a narrow-moat retailer burning cash. But the trend was strongly positive: every additional buyer and seller deepened the network, and scale kept lowering unit costs that rivals couldn’t match. The moat widened year after year, and later the cloud business stacked a second advantage on top of the first. A width-only screen would have waved it through as unremarkable. The direction was the whole story.

The three states and the five erosion patterns

Dorsey’s framework gives the trend three states. Positive (the moat is widening): returns on capital climbing over several years, pricing power that customers accept without walking, lock-in deepening, management reinvesting in the core rather than buying unrelated businesses. Stable (the moat is holding): returns in a steady band, share flat, prices tracking inflation, no disruption on the horizon. Stable is not a problem. Most great compounders spend most of their lives here, and the compounding comes from reinvesting the cash, not from the moat getting wider. Negative (the moat is eroding): the one that should change your behavior.

Negative trend rarely announces itself in a single bad number. It arrives through one of five patterns, and the value of knowing them is that you can see the cause before the income statement shows the effect:

• Outside technology.The most dangerous, because it comes from an adjacent category, not a direct rival. Digital imaging didn’t compete with Kodak inside photography; it changed what photography was. Newspapers, long-distance carriers, and music publishers were all dismantled the same way.
• Customer concentration. A once-fragmented buyer base consolidates and pricing power flips from supplier to buyer. When a single retailer becomes a fifth of your revenue, your brand still exists but you can no longer fully charge for it.
• Irrational competitors.State-backed firms or cash-burning challengers that don’t need to earn a normal return can depress everyone’s margins for years, even while losing money themselves.
• Growth into no-moat ground.Self-inflicted. The core stays strong, but management spends the cash flow expanding into businesses where it has no advantage, dragging the whole company’s capital efficiency down with it.
• Loss of pricing power.Usually the first crack to show. Price hikes that used to pass start meeting resistance. When low-cost third-party providers gave Oracle’s customers an alternative to its maintenance contracts, the pushback on annual increases showed up well before any line in the financials did.

A quarterly monitoring checklist

You don’t need a Bloomberg terminal to track trend. You need four readings, taken in the same order every quarter, and the discipline to watch the change rather than the level:

• Three-year return-on-capital trend.Not this quarter’s figure, the slope across roughly three years, with acquisitions and capex cycles set aside. Rising is the cleanest evidence a moat is widening; a steady multi-year decline that management can’t explain is the cleanest evidence it’s eroding.
• Pricing power.Read the earnings-call language. When a company starts talking about a “competitive pricing environment” or being “thoughtful” about increases, that is the leading indicator, often a year or two ahead of the margin.
• Churn and retention. Are customers staying longer and buying more, or are renewals getting shorter and harder? Deepening lock-in is a widening moat; rising churn is a narrowing one, and it moves before revenue does.
• Capex direction.Is management reinvesting in the core advantage, or diverting cash into adjacencies where it has no edge? Follow the money; it tells you whether they’re widening the moat or quietly abandoning it.

None of these proves anything on its own, and one weak reading in a quarter is noise, not a verdict. But three of the four turning the same direction for a year is a signal worth acting on, in either direction.

Where the ranks see it first

This is the hard part of trend-watching: it’s slow, it’s quiet, and a moat erodes for years before the share price admits it. The Obermatt ranks are built to compress that lag. A company’s Value and Safetyranks are measured against its true peers and tracked across multiple cycles, so the relevant thing isn’t the headline number, it’s the line over time. A moat that is widening looks like a rank that holds high while rivals drift back toward the pack. A moat that is eroding looks like a peer-relative rank sliding year over year, because peers are gaining on a company that used to hold them off. That slide tends to appear before the trend reaches the multiple, which is the entire point of watching it. Safety, in particular, works as a moat-stability proxy: a balance sheet quietly weakening relative to peers is often the first financial fingerprint of a defense being stormed.

So the principle is this: own the direction, not the snapshot. A wide moat is worth nothing if the trend has turned, and a narrow one can be worth a great deal if it’s thickening. The concrete action takes ten minutes a quarter. Pick your holdings, run the four readings, and write down whether each name’s moat is widening, holding, or eroding. Do that four times a year and you will see the trend turn long before the market builds it a headline.