Klarman

• Value investing is simple to understand but difficult to implement. The hard part is discipline, patience, and judgment. Investors need discipline to avoid the many unattractive pitches that are thrown, patience to wait for the right pitch, and judgment to know when it is time to swing.
• Given how hard it is to accumulate capital and how easy it can be to lose it, it is astonishing how many investors almost single-mindedly focus on return, with a nary of thought about risk. Investors seem to be largely oblivious to off the radar events and worstcase scenarios. History suggests that a reordering of priorities lies in the not too distant future.
• Selling, in particular can be a challenge; many investors are tempted to become more optimistic when a security is performing well. This temptation must be resisted; tax considerations aside, when a security reaches full valuation, there is no longer a reason to own it.
• Value investors own bargains — securities trading at a discount to underlying value which confer a margin of safety. This doesn’t mean those holdings can’t or won’t drop in price; it means that when they decline, they’ll be an even better bargain to which you are likely to seek to add.
• The stock market is the story of cycles and of the human behavior that is responsible for overreactions in both directions.
• Value investing is intellectually elegant. You’re basically buying bargains. It also appeals because all the studies demonstrate that it works. People who chase growth, who chase highfliers, inevitably lose because they paid a premium price. They lose to the people who have more patience and more discipline.
• The disciplined pursuit of bargains makes value investing very much a risk-averse approach. The greatest challenge for value investors is maintaining the required discipline. Being a value investor usually means standing apart from the crowd, challenging conventional wisdom, and opposing the prevailing investment winds. It can be a very lonely undertaking. A value investor may experience poor, even horrendous, performance compared with that of other investors or the market as a whole during prolonged periods of market overvaluation. Yet over the long run the value approach works so successfully that few, if any, advocates of the philosophy ever abandon it.
• The future is unpredictable. No one knows whether the economy will shrink or grow (or how fast), what the rate of inflation will be, and whether interest rates and share prices will rise or fall. Investors intent on avoiding loss consequently must position themselves to survey and even prosper under any circumstances.
• It would be a serious mistake to think that all the facts that describe a particular investment are or could be known. Not only may questions remain unanswered; all the right questions may not even have been asked. Even if the present could somehow be perfectly understood, most investments are dependent on outcomes that cannot be accurately foreseen. Even if everything could be known about an investment, the complicating reality is that business values are not carved in stone. If you cannot be certain of value, after all, then how can you be certain that are you buying at a discount? The truth is you cannot. Buying at a discount creates a margin of safety for the investor—room for imprecision, error, bad luck or the vicissitudes of volatile markets and economies. 
• Investing is mean reverting. What has outperformed lately will not, and cannot, grow to the sky. Sustained out performance in any particular sector of the markets is eventually borrowed from the future, to be given back either slowly through sustained under performance or quickly through price declines. What has worked lately is popular, widely owned, and bid up in price, and therefore generally anathema to good future results. But human nature makes it extremely difficult for people to embrace what has recently fared poorly.
• For any fundamental-based investor, this is complete hogwash. Investment come in the following varieties: undervalued, fairly valued, and overvalued. Price is everything, and every investment is undervalued at one price, fairly valued at a higher price, and overvalued at some still higher price. You buy the first, avoid the second, and sell the third. Having a goal of diversification, rather than owning value, causes investors to take their eye off the ball. It is a refuge of investment wimps, owning a little bit of everything to avoid being wrong, but thereby ensuring never being really right either.