以前写过类似的短文，结合最近对中海油的投资，作为一位在石油勘探开发行业工作数十年的人，面对这次极为难得的投资机会，尽管将自己认为可以接受的最大仓位用到了海油上，但是感觉投入得还是不够，回头看，将60%而不是40%的资金投入到海油上，会是一个更好的选择。
所以，今天将原文拿出来，注解给大家看看。
What are your views on diversification?
问：你对多元化的观点是什么？
I have 2 views on diversification. If you are a professional and have confidence, then I would advocate lots of concentration. For everyone else, if it's not your game, participate in total diversification. The economy will do fine over time. Make sure you don't buy at the wrong price or the wrong time. That's what most people should do, buy a cheap index fund, and slowly dollar cost average into it. If you try to be just a little bit smart, spending an hour a week investing, you're liable to be really dumb. If it's your game, diversification doesn't make sense. It's crazy to put money into your 20th choice rather than your 1st choice. “Lebron James” analogy. If you have Lebron James on your team, don't take him out of the game just to make room for someone else. If you have a harem of 40 women, you never really get to know any of them well.
对多元化持双重观点：对于专业投资者，应该集中；对于非专业投资者应该充分多元化。对多数人，应该买入交易费更低的指数基金，并慢慢买入，通过摊薄成本获得低成本。
Charlie and I operated mostly with 5 positions. If I were running 50, 100, 200 million,
I would have 80% in 5 positions, with 25% for the largest. In 1964 I found a position I was willing to go heavier into, up to 40%. I told investors they could pull their money out. None did. The position was American Express after the Salad Oil Scandal. In 1951 I put the bulk of my net worth into GEICO. Later in 1998, LTCM was in trouble. With the spread between the on-the-run versus off-the-run 30 year Treasury bonds, I would have been willing to put 75% of my portfolio into it. There were various times I would have gone up to 75%, even in the past few years. If it's your game and you really know your business, you can load up.
巴菲特与芒格经常将资金主要投在5个目标上，如果资金量较小，会把80%的资金投在这5个目标上，其中仓位最大的可以达到25%。他在1964年曾经将最喜爱的个股上投入达到40%。（大致相对于我对中海油的投资比例，现在持仓已经高过50%，但那是因为股价上涨导致的）巴菲特认为自己应该遇到过一些极佳的机会，如果机会极佳，可以将在一个机会上的资金量上到总资金的75%。
Over the past 50-60 years, Charlie and I have never permanently lost more than 2%
of our personal worth on a position. We've suffered quotational loss, 50% movements. That's why you should never borrow money. We don't want to get into situations where anyone can pull the rug out from under our feet.
In stocks, it's the only place where when things go on sale, people get unhappy. If I like a business, then it makes sense to buy more at 20 than at 30. If McDonalds
reduces the price of hamburgers, I think it's great.
·
Source: Emory's Goizueta Business
School and McCombs School of Business at UT Austin；Time:
February 2008
-------------------------------------------------------------------
The question is about diversification. I have a dual answer to that. If you are not a professional investor. If your goal is not to manage money to earn a significantly better return than the world, then I believe in extreme diversification. I believe 98% - 99% who invest should extensively diversify and not trade, so that leads them to an index fund type of decision with very low costs. All they are going to do is own part of America. And they have made a decision that owning a part of America is worthwhile. I don't quarrel with that at all. That is the way they should approach it unless they want to bring an intensity to the game to make a decision and start evaluating businesses. Once you are in the businesses of evaluating businesses and you decide that you are going to bring the effort and intensity and time involved to get that job done, then I think diversification is a terrible mistake to any degree. I got asked that question the other day at SunTrust. If you really know businesses, you probably shouldn't own more than six of them.
巴菲特认为仅有1%-2%的普通投资者可以进行集中投资（估计90%以上的投资者认为自己属于这个1%-2%），绝大多数投资者应该充分多元化并减少交易，以便建立一个类似指数基金的多元化组合。但是你如何真的了解生意以后，通过花费更多是时间和精力进行投资，那么，持有的个股就不应超过6只，他自己可能会仅选3只自己认为最好的股票进行投资。
If you can identify six wonderful businesses, that is all the diversification you need. And you will make a lot of money. And I can guarantee that going into a seventh one instead of putting more money into your first one is gotta be a terrible mistake. Very few people have gotten rich on their seventh best idea. But a lot of people have gotten rich with their best idea. So I would say for anyone working with normal capital who really knows the businesses they have gone into, six is plenty, and I probably have half of what I like best. I don't diversify personally. All the people I've known that have done well with the exception of Walter Schloss, Walter diversifies a lot. I call him Noah, he has two of everything.
·
Source: Lecture at the University
of Florida Business School；Time: October 15th 1998
-------------------------------------------------------------------
[Q - How do you get confident enough with that [smaller] level of diversification?]
问：持股数量较少，如何获得信心？
Warren Buffett: If we were running only our own money, putting 75% of our net worth in a single position is not a problem if it is something we really have high confidence in. Putting 500% or more of your net worth in a position is a problem. Several times I have had 75% of my non-Berkshire net worth in a situation. You will see things where it would be a mistake not to act. You won't see them often, and the press and your friends won't be talking about them. Wouldn't you say, Charlie? 75% is not a real significant amount?
如果钱是自己的，那么将75%的资金投入到自己极具信心的股票上是没问题的。500%的比例才会有问题。少数情况下，巴菲特会将自己没有投入到伯克希尔的资金的75%投到一只股票上。
Charlie Munger: Sometimes, I have had more than 100% in an individual investment.
芒格说自己有时候将100%以上的资金投到一只证券上。
Warren Buffett: You just had a good banker. Look at LTCM — they put 25x their money in things that had to converge but couldn't play out the hand. There are people in this room with more than 90% of their worth in Berkshire. I saw things in 2002 in junk bonds that would have been worth going heavily into. You could have bought Cap Cities in 1974 — selling for one-third the property value, with the best manager, and in a good business. You could have put 100% in Coca-Cola when we bought it and that wouldn't have been a dangerous position.
有人将90%以上的资金投到伯克希尔，当巴菲特买入可口可乐的时候，如果有人将100%的资金投在可口可乐上，那一样是没有问题的。
Charlie Munger: Students learn corporate finance at business schools. They are taught that the whole secret is diversification. But the exact rule is the opposite. The‘know-nothing' investor should practice diversification, but it is crazy if you are an expert. The goal of investment is to find situations where it is safe not to diversify. If you only put 20% into the opportunity of a life-time, you are not being rational. Very seldom do we get to buy as much of any good idea as we would like to.
芒格认为金融类学生学习多元化的原理是错误的，事情应该正好相反。对于不懂行的，应该多元化，但是对于专业人士，应该寻找那些可以集中投资的机会，如果将20%的资金投入到一生中很难遇到的机会，那是非理性的。
·
Source: Annual Meeting 2008
Boodell Notes；Time: 2008