在2000年之前的二，三年，著名投资者Howard Marks 和巴菲特都曾经以非常正式的方式公开提醒股市处于非理性的状态。他们的正确判断在2，3年之后被印证了 。
目前 SP PE Ratio 25, 市场中认为股市过热的人远比２０００年之前要多。如果假设这个判断是正确的，市场也是需要一段时间来印证的， 比如２，３年的时间 。以SP市场平均资本回报率10%为参考，三年的复利是33%，所以今天的市场价格三年后SP PE ＲＡＴＩＯ是１８－１９，这是一个完全合理的市场价格，所以无论市场以何种理由借口维持三年，今天的价格就成为了一个合理的价格。
如果市场未来保持10%的年均增长，三年后估值水平等同于现在，那么今天市场跌不下去， 未来也可能跌不下去。
市场只有在未来3年里有大大超过33%的增长幅度的情况下，才会有比今天更大概率的有一定大幅度的估值回归下跌。
市场长期维持现状，等待估值慢慢趋于合理范围也是一个选项。
At Berkshire we focus almost exclusively on the valuations of individual companies, looking only to a very limited extent at the valuation of the overall market. Even then, valuing the market has nothing to do with where it's going to go next week or next month or next year, a line of thought we never get into. The fact is that markets behave in ways, sometimes for a very long stretch, that are not linked to value. Sooner or later, though, value counts. - 巴菲特1999年公开演讲
为什么老巴现阶段投资苹果，因为市场的高低从来不是他投资的重要参考依据。
From an interview with Charlie Munger at the University of Michigan Ross School of Business. For a couple of hours, Munger talks in front of a large audience to Becky Quick of CNBC then takes questions from students and faculty.
"Warren and I have not made our way in life by making successful macroeconomic predictions and betting on our conclusions.
Our system is to swim as competently as we can and sometimes the tide will be with us and sometimes it will be against us. But by and large we don't much bother with trying to predict the tides because we plan to play the game for a long time.
I recommend to all of you exactly the same attitude.
It's kind of a snare and a delusion to outguess macroeconomic cycles...very few people do it successfully and some of them do it by accident. When the game is that tough, why not adopt the other system of swimming as competently as you can and figuring that over a long life you'll have your share of good tides and bad tides?"
对大多数普通人，芒格的建议是值得参考的。
