The line separating investment and speculation, which is never bright and clear, becomes blurred still further when most market participants have recently enjoyed triumphs. Nothing sedates rationality like large doses of effortless money. After a heady experience of that kind, normally sensible people drift into behavior akin to that of Cinderella at the ball. They know that overstaying the festivities -- that is, continuing to speculate in companies that have gigantic valuations relative to the cash they are likely to generate in the future -- will eventually bring on pumpkins and mice. But they nevertheless hate to miss a single minute of what is one helluva party. Therefore, the giddy participants all plan to leave just seconds before midnight. There’s a problem, though: They are dancing in a room in which the clocks have no hands.

The approach and strategies are very similar in that you gather all the information you can and then keep adding to that base of information as things develop. You do whatever the probabilities indicated based on the knowledge that you have at that time, but you are always willing to modify your behaviour or your approach as you get new information. In bridge, you behave in a way that gets the best from your partner. And in business, you behave in the way that gets the best from your managers and your employees.

I wouldn’t mind going to jail if I had three cellmates who played bridge.

I am out of step with present conditions. When the game is no longer played your way, it is only human to say the new approach is all wrong, bound to lead to trouble, and so on. On one point, however, I am clear. I will not abandon a previous approach whose logic I understand ( although I find it difficult to apply ) even though it may mean foregoing large, and apparently easy, profits to embrace an approach which I don't fully understand, have not practiced successfully, and which possibly could lead to substantial permanent loss of capital. In a letter to his partners in the stock market frenzy of 1969.

I never buy anything unless I can fill out on a piece of paper my reasons. I may be wrong, but I would know the answer to that. “I’m paying $32 billion today for the Coca Cola Company because...” If you can’t answer that question, you shouldn’t buy it. If you can answer that question, and you do it a few times, you’ll make a lot of money.

We will only do with your money what we would do with our own.

When a management with a reputation for brilliance tackles a business with a reputation for bad economics, it is usually the reputation of the business that remains intact.

The strategy we've adopted precludes our following standard diversification dogma. Many pundits would therefore say the strategy must be riskier than that employed by more conventional investors. We disagree. We believe that a policy of portfolio concentration may well decrease risk if it raises, as it should, both the intensity with which an investor thinks about a business and the comfort-level he must feel with its economic characteristics before buying into it.

I call investing the greatest business in the world because you never have to swing. You stand at the plate, the pitcher throws you General Motors at 47! U.S. Steel at 39! and nobody calls a strike on you. There's no penalty except opportunity lost. All day you wait for the pitch you like; then when the fielders are asleep, you step up and hit it.

We don't get paid for activity, just for being right. As to how long we'll wait, we'll wait indefinitely.

In a bull market, one must avoid the error of the preening duck that quacks boastfully after a torrential rainstorm, thinking that its paddling skills have caused it to rise in the world. A right-thinking duck would instead compare its position after the downpour to that of the other ducks on the pond. Letter to Berkshire Hathaway shareholders, 1997.

Berkshire’s arbitrage activities differ from those of many arbitrageurs. First, we participate in only a few, and usually very large, transactions each year. Most practitioners buy into a great many deals perhaps 50 or more per year. With that many irons in the fire, they must spend most of their time monitoring both the progress of deals and the market movements of the related stocks. This is not how Charlie nor I wish to spend our lives. (What’s the sense in getting rich just to stare at a ticker tape all day?)

The important thing is to keep playing, to play against weak opponents and to play for big stakes. November 2002 talking with students at Gaston Hall.

We have tried occasionally to buy toads at bargain prices with results that have been chronicled in past reports. Clearly our kisses fell flat. We have done well with a couple of princes - but they were princes when purchased. At least our kisses didn't turn them into toads. And, finally, we have occasionally been quite successful in purchasing fractional interests in easily-identifiable princes at toad-like prices. 1981 Chairman's Letters to Shareholders.

For some reason, people take their cues from price action rather than from values. What doesn’t work is when you start doing things that you don't understand or because they worked last week for somebody else. The dumbest reason in the world to buy a stock is because it's going up.

It’s got to be the best intellectual exercise out there. You’re seeing through new situations every ten minutes…In the stock market you don’t base your decisions on what the market is doing, but on what you think is rational….Bridge is about weighing gain/loss ratios. You’re doing calculations all the time.

I just don't see anything available that gives any reasonable hope of delivering such a good year and I have no desire to grope around, hoping to 'get lucky' with other people's money. I am not attuned to this market environment, and I don't want to spoil a decent record by trying to play a game I don't understand just so I can go out a hero.

First, many in Wall Street - a community in which quality control is not prized - will sell investors anything they will buy.

Our future rates of gain will fall far short of those achieved in the past. Berkshire's capital base is now simply too large to allow us to earn truly outsized returns. If you believe otherwise, you should consider a career in sales but avoid one in mathematics (bearing in mind that there are really only three kinds of people in the world: those who can count and those who can't). 1998 Chairman's Letter to Shareholders.

The key to investing is not assessing how much an industry is going to affect society, or how much it will grow, but rather determining the competitive advantage of any given company and, above all, the durability of that advantage.

The fact that people will be full of greed, fear or folly is predictable. The sequence is not predictable.

Like an oversexed guy in a whorehouse. Now is the time to invest and get rich. Answering to the question: "How do you feel?", in an interview with Forbes in October 1974.

In my early days as a manager I, too, dated a few toads. They were cheap dates - I've never been much of a sport - but my results matched those of acquirers who courted higher-price toads. I kissed and they croaked. On acquiring bad companies for cheap prices.

Despite three years of falling prices, which have significantly improved the attractiveness of common stocks, we still find very few that even mildly interest us. That dismal fact is testimony to the insanity of valuations reached during The Great Bubble. Unfortunately, the hangover may prove to be proportional to the binge. March 2003.