Sources of Sustainable Advantage
A checklist of the durable moats that protect a business.
‘Sustainable competitive advantage' is less a framework than a handy checklist of the things that actually keep competitors out. The question behind all of them is the same: what genuinely stops a rival — even a well-funded one — from copying you? These are the eight moats.
TL;DR · Key Takeaways
What you will be able to do
- Recall the eight common sources of a durable competitive moat.
- Assess which moats a firm holds, how deep, and how durable.
- Distinguish a structural moat from a mere head start or hot product.
- Combine it with VRIO to test whether a claimed advantage is real.
- Use it to read the threat of new entrants in an industry.
The eight moats
Network effects (each user adds value for the next), scale economies (lower unit cost as you grow), switching costs (painful to leave), brand loyalty (trust that resists cheaper rivals), intellectual property (patents and secrets), innovation (staying ahead faster than rivals catch up), locked-in supply (exclusive access to a scarce input), and distribution control (owning the channel or prime locations).
How to use it
Check a firm against the eight: which moats does it actually hold, how deep are they, and how durable? The more moats, and the deeper, the stronger the defence. It's the natural complement to VRIO — the moats name the sources of advantage; VRIO tests whether a given one is real.
Mistaking a head start for a moat
Being first, or having a hot product right now, is not a moat — a well-funded rival can catch up. A true moat is a structural reason they can't easily copy you. Always ask what actually does the stopping.
How wide is the moat?
A food-delivery app is the market leader and tells investors it has a strong competitive moat. How would you assess that?
I'd run them against the moat sources. Network effects: yes — more restaurants attract more diners and vice versa, a genuine two-sided moat. Scale economies: partially — denser delivery lowers cost per order. Switching cost: weak — both diners and restaurants happily multi-home across apps, so loyalty is thin. Brand: moderate. So the moat is real but narrower than claimed — it rests mostly on network effects and density, and is vulnerable precisely where switching costs are low. A well-funded rival buying its way to density is the real threat.
Checks against the moat list.
Rather than accept ‘strong moat', the candidate named which moats existed, how deep, and where the defence was thin — which is the honest read investors actually need.
Where this connects
This checklist sits right beside VRIO (which tests any single moat) and informs the threat-of-entrants force in Porter's Five Forces — strong moats are exactly what keep new entrants out.