In medieval times, a moat was a trench filled with water surrounding a castle, designed to keep invaders out. In investing, the term economic moat – popularised by Warren Buffett – describes a company’s ability to maintain a durable competitive advantage that protects its profits from competitors.
Why does this matter to investors? Companies with strong economic moats tend to generate consistent earnings, higher margins, and long-term market dominance. A strong moat doesn’t just keep competitors at bay – it allows a company to continue compounding returns over time.
Types of Economic Moats
Not all moats are created equal. Some are deep, some are wide, and some are both. Here’s how to think about them:
- Deep and wide moat: The gold standard. Competitors struggle to breach it, and even if they try, they can be seen coming from miles away. Example: Netwealth (ASX:NWL) – its competitive position remains strong despite Hub24 (ASX:HUB) catching up, and it can continue taking market share for years.
- Wide but shallow moat: Easy to cross, but it slows competitors down, and the company can see them coming. Example: Woolworths (ASX:WOW) – it dominates groceries, but competition constantly marches through its moat (e.g., Aldi).
- Narrow but deep moat: Hard to cross, but once breached, the advantage is lost quickly. Example: Aurizon Holdings (ASX: AZJ) – Australia’s largest rail freight operator. Its efficient scale and cost advantages make it difficult to compete with, but its moat is narrow as it relies on coal transportation, making it vulnerable to regulatory changes and shifts in energy demand.
A key takeaway: A shrinking but deep, wide moat can be more valuable than a growing but shallow moat. A strong position eroded slowly (like Netwealth’s) can still be more durable than a company constantly fending off competitors (like Woolworths).
What Creates an Economic Moat?
A company’s moat can come from several sources, including:
- Brand Strength & Customer Loyalty – Companies like Apple and Woolworths benefit from strong customer habits and brand perception.
- Cost Advantages & Scale – Amazon and BHP (ASX:BHP) can undercut competitors due to their size and operational efficiency.
- Network Effects – The more users a platform has, the stronger its moat. Think ASX (ASX:ASX), Facebook (Meta), or Netwealth.
- Regulatory Barriers – Banks, utilities, and healthcare providers often benefit from government-imposed restrictions on competition.
- Switching Costs – Companies like Pro Medicus (ASX:PME) and Xero (ASX:XRO) benefit from customers who find it costly or difficult to change providers.
Why Moat Size Isn’t Everything
Investors often focus on the size of a moat, but it’s also important to consider durability. A company with a shrinking yet strong moat (like Netwealth) can still outperform a company with a growing but fragile moat. But if a company with a narrow moat starts to see it disappear, it can be disastrous.
Moats evolve over time – some expand, others erode. PME’s moat, for example, has remained surprisingly strong despite expectations it would shrink. Meanwhile, a company like Objective Corporation (ASX:OCL) has a great moat, but it may not be getting any larger.
What Investors Should Look For
- Moat quality > sheer size – A deep, wide moat that erodes slowly is often preferable to a shallow one expanding quickly.
- Moat trajectory matters – Is it strengthening, stable, or weakening? A strong but shrinking moat can still offer years of protection.
- Think long-term – Companies with moats that provide lasting advantages tend to generate the best long-term returns.
Assessing economic moats requires more than just identifying a competitive advantage – it’s about understanding how that advantage evolves over time. Smart investors don’t just ask “Does this company have a moat?” They ask, “Will this moat still be strong in five or ten years?”
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Disclosure: The author of this article, Patrick Poke, owns shares in NWL and Amazon, but does not own shares in any of the other companies mentioned. The author will not trade any of the companies mentioned shares for at least 48 hours following the publication of this article. This article is not intended to form the basis of an investment decision and is not a recommendation. Any statements that are advice under the law are general advice only. The author has not considered your investment objectives or personal situation. Any advice is authorised by Claude Walker (AR 1297632), Authorised Representative of Ethical Investment Advisers Pty Ltd (ABN 26108175819) (AFSL 343937).
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