Warren Buffett's Words on Efficient Markets

Yes, Virginia, you can occasionally find markets that are ridiculously inefficient – or at least you can find them anywhere except at the finance departments of some leading business schools.

Amazon (AMZN) bonds:

For example, in 2001 and 2002 we purchased €310 million Amazon.com, Inc. 6 7/8 of 2010 at 57% of par. At the time, Amazon bonds were priced as “junk” credits, though they were anything but.
The Euro denomination of the Amazon bonds was a further, and important, attraction for us. The Euro was at 95¢ when we bought in 2002. Therefore, our cost in dollars came to only $169 million. Now the bonds sell at 102% of par and the Euro is worth $1.47. In 2005 and 2006 some of our bonds were called and we received $253 million for them. Our remaining bonds were valued at $162 million at yearend. Of our $246 million of realized and unrealized gain, about $118 million is attributable to the fall in the dollar. Currencies do matter.

Put options:

…we have sold [various put options] on four stock indices (the S&P 500 plus three foreign indices). These puts had original terms of either 15 or 20 years and were struck at the market. We have received premiums of $4.5 billion, and we recorded a liability at yearend of $4.6 billion. The puts in these contracts are exercisable only at their expiration dates, which occur between 2019 and 2027, and Berkshire (BRK.A) will then need to make a payment only if the index in question is quoted at a level below that existing on the day that the put was written. Again, I believe these contracts, in aggregate, will be profitable and that we will, in addition, receive substantial income from our investment of the premiums we hold during the 15- or 20-year period.
Two aspects of our derivative contracts are particularly important. First, in all cases we hold the money, which means that we have no counterparty risk.
Second, accounting rules for our derivative contracts differ from those applying to our investment portfolio. In that portfolio, changes in value are applied to the net worth shown on Berkshire’s balance sheet, but do not affect earnings unless we sell (or write down) a holding. Changes in the value of a derivative contract, however, must be applied each quarter to earnings.
Thus, our derivative positions will sometimes cause large swings in reported earnings, even though Charlie and I might believe the intrinsic value of these positions has changed little. He and I will not be bothered by these swings – even though they could easily amount to $1 billion or more in a quarter – and we hope you won’t be either. You will recall that in our catastrophe insurance business, we are always ready to trade increased volatility in reported earnings in the short run for greater gains in net worth in the long run. That is our philosophy in derivatives as well.

Wisdom of the crowds:

“Please, God, Just One More Bubble.” Unfortunately, this wish was promptly granted, as just about all Americans came to believe that house prices would forever rise. That conviction made a borrower’s income and cash equity seem unimportant to lenders, who shoveled out money, confident that HPA – house price appreciation – would cure all problems. Today, our country is experiencing widespread pain because of that erroneous belief.
As house prices fall, a huge amount of financial folly is being exposed. You only learn who has been swimming naked when the tide goes out – and what we are witnessing at some of our largest financial institutions is an ugly sight.

Sources:

Letter to Shareholders
Buffett’s State of the World: There’s Folly in Wonderland
Profit party’s over for insurance industry