The Moat Index · Primary SEC filings
SEC filing scores, versioned history, and as‑of backtests
The Moat Index computes business-quality evidence from primary filings, preserves each model reading, and backtests only what was knowable at the time. Use it to examine whether a wonderful business may be on sale — not as a prediction, analyst rating, or investment recommendation.
Would Buffett buy this?
How the score works →The Playbook
Read it in depth →Twelve durable principles behind the score. Each one maps to something the Moat Index actually measures — so the ideas and the numbers teach each other.
Buy businesses, not tickers
A stock is a fractional ownership stake in a real company, not a blinking symbol.
02Stay inside your circle of competence
You don't need to understand every business — only the ones you own.
03Demand a margin of safety
Buy at enough of a discount to be wrong and still be okay.
04Look for durable moats
Favor businesses that competitors find structurally hard to attack.
05Judge management like a partner
You are handing your capital to these people. Act like it.
06Let earnings power guide you, not price charts
Value follows the cash a business can generate, not the shape of its chart.
07Be fearful when others are greedy
Price follows mood in the short run. Use the mood; don't join it.
08Hold forever — or at least act like it
The big money is made by owning great businesses through compounding, not by trading them.
09Ignore the crowd, not the facts
You are neither right nor wrong because others agree with you.
10Keep cash for the fat pitch
Cash is an option on future bargains, and investing has no called strikes.
11Avoid leverage and what you don't understand
Never risk what you have and need for what you don't have and don't need.
12Keep learning — read every day
Knowledge compounds exactly like capital.
The one chart that explains it all
Benjamin Graham imagined the market as a manic business partner — Mr. Market — who shows up every day quoting a different price for the same business. Some days euphoric, some days despondent, his quotes swing far around what the business is actually worth.
The Moat Score measures the solid line — the business. The margin-of-safety gauge tells you when the dotted line — the price — is offering you a bargain.
Start with these guides
All articles →How to Think About “What Would Buffett Buy?”
The useful version of the question is not which ticker Buffett would pick — it's the four filters he would run any business through.
7 min read →Core ConceptMargin of Safety, Explained With Simple Numbers
The three most important words in investing are a bridge-building idea: build for trucks twice as heavy as the ones you expect.
6 min read →Business AnalysisThe Five Kinds of Economic Moats, With Examples
High profits attract competition the way honey attracts bears. A moat is whatever keeps the bears out — and there are only about five kinds.
8 min read →