Abstract: We analyze Berkshire Hathaway’s equity portfolio over the 1976 to 2006 period and explore potential explanations for its superior performance. Contrary to popular belief, we find Berkshire Hathaway invests primarily in large-cap growth rather than “value” stocks. Over the period the portfolio beat the benchmarks in 27 out of 31 years, on average exceeding the S&P 500 Index by 11.14%, the value-weighted index of all stocks by 10.92%, and a Fama and French characteristic-based portfolio by 8.56% per year. Although beating the market in all but four years can statistically happen due to chance, incorporating the magnitude by which the portfolio beats the market makes a luck explanation extremely unlikely even after taking into account ex-post selection bias. We find that Berkshire Hathaway’s portfolio is concentrated in relatively few stocks with the top five holdings averaging 73% of the portfolio value. While increased volatility is normally associated with higher concentration we show the volatility of the portfolio is driven by large positive returns and not downside risk. The market appears to under-react to the news of a Berkshire Hathaway stock investment since a hypothetical portfolio that mimics the investments at the beginning of the following month after they are publicly disclosed also earns significantly positive abnormal returns of 10.75% over the S&P 500 Index. Our evidence suggests the Berkshire Hathaway triumvirates of Warren Buffett, Charles Munger, and Lou Simpson posses’ investment skill unlikely to be explained by Efficient Market Theory.

Abstract: This paper examines whether a simple accounting-based fundamental analysis strategy, when applied to a broad portfolio of high book-to-market firms, can shift the distribution of returns earned by an investor. I show that the mean return earned by a high bookto- market investor can be increased by at least 7½ percent annually through the selection of financially strong high BM firms while the entire distribution of realized returns is shifted to the right. In addition, an investment strategy that buys expected winners and shorts expected losers generates a 23 percent annual return between 1976 and 1996 and the strategy appears to be robust across time and to controls for alternative investment strategies. Within the portfolio of high BM firms, the benefits to financial statement analysis are concentrated in small and medium sized firms, companies with low share turnover and firms with no analyst following, yet this superior performance is not dependent on purchasing firms with low share prices. A positive relationship between the sign of the initial historical information and both future firm performance and subsequent quarterly earnings announcement reactions suggests that the market initially under-reacts to the historical information. In particular, 1/6th of the annual return difference between ex ante strong and weak firms is earned over the four three-day periods surrounding these quarterly earnings announcements. Overall, the evidence suggests that the market does not fully incorporate historical financial information into prices in a timely manner.