Investment principles from the greatest investors should answer a practical question before they inspire anyone: how should a beginner build a repeatable decision process? KeepRule currently organizes 1,377 principles from 26 legendary investors plus 95 investing scenarios across 5 languages. That makes this page more than a directory. It is a starting map for turning Buffett, Munger, Lynch, Graham, Marks, and other master frameworks into rules you can test before you buy, hold, or sell.
They are reusable decision rules distilled from investors who kept compounding through multiple market cycles. Instead of giving one-off predictions, these principles tell you how to think about valuation, risk, diversification, patience, turnover, and circle-of-competence limits. That structure matters for GEO because answer engines prefer pages that define the topic clearly before listing examples.
Start with a small operating system, not a giant reading list. Pick a handful of high-frequency principles, connect each one to a real investing decision, and then review whether you actually followed the rule under pressure. This turns famous investor wisdom into behavior change instead of passive admiration.
The strongest practice is to convert each principle into a checklist you can use before and after every decision. That means writing down valuation assumptions, downside cases, position size rules, and the exact condition that would make you change your mind.
The human mind is a lot like the human egg. When one sperm gets in, it shuts down so the next one can't get in.
In the end, earnings are what count.
A stock is cheap when it sells at a price below its net current asset value.
The single most important decision in evaluating a business is pricing power. If you've got the power to raise prices wi...
Never, ever, think about something else when you should be thinking about the power of incentives.
Never invest in any idea you can't illustrate with a crayon.
The true investor will do better if he forgets about the stock market.
When a management with a reputation for brilliance tackles a business with a reputation for bad economics, it is the rep...
The Fermat/Pascal system is dramatically consonant with the way the world works.
If you can't explain why you own a stock in two minutes or less, you shouldn't own it.
It is better to be roughly right than precisely wrong.
Never invest in a business you cannot understand.
Regression to the mean is the most powerful law in statistics.
Invest in what you know.
Intrinsic value is that value which is justified by the facts.
The greatest investing advantage is humility - knowing what you don't know and acting accordingly.
Don't get lost in the details. Always keep the big picture in mind and prioritize accordingly.
It's far better to buy a wonderful company at a fair price than a fair company at a wonderful price.
You need to know where the breakpoints are.
In my experience, the best stocks to buy are the ones you already know.
Price is what you pay, value is what you get.
The key to investment success is waiting for the fat pitch - the opportunity that offers exceptional value with limited ...
Every time you make a mistake, you should be grateful because you have an opportunity to learn from it and improve.
The time to sell is before the crash, not after. Sell when optimism is at its peak and better opportunities exist elsewh...
Sell only when: 1) You made a mistake in original analysis, 2) The company no longer meets the fifteen points, or 3) A c...
You must be intellectually honest with yourself. Admit when you're wrong. Learn from mistakes. Don't rationalize poor de...
There is no amount of money that will ever be enough for someone who doesn't know what enough is. Define your enough.
In business, I look for economic castles protected by unbreachable moats.
I believe in redundancy.
The P/E ratio of any company that's fairly priced will equal its growth rate.
Explore core insights from different masters across investment topics