Imitation is the Sincerest Form of Flattery: Warren Buffett and Berkshire Hathaway
Abstract:
We analyze the performance of Berkshire Hathaway's equity portfolio and explore potential explanations for its superior performance. Contrary to popular belief we show Berkshire's investment style is best characterized as a large-cap growth. We examine whether Berkshire's investment performance is due to luck and find that beating the market in 28 out of 31 years places it in the 99.99 percentile; however, incorporating the magnitude by which Berkshire beats the market makes the “luck” explanation unlikely even after taking into account ex-post selection bias. After adjusting for risk we find that Berkshire's performance cannot be explained by assuming high risk. From 1976 to 2006 Berkshire's stock portfolio beats the S&P 500 Index by 14.65%, the value-weighted index of all stocks by 10.91%, and the Fama and French characteristic portfolio by 8.56% per year. The market also appears to under-react to the news of a Berkshire stock investment since a hypothetical portfolio that mimics Berkshire's investments created the month after they are publicly disclosed earns positive abnormal returns of 14.26% per year. Overall, the Berkshire Hathaway triumvirates of Warren Buffett, Charles Munger, and Lou Simpson posses' investment skill consistent with a number of recent papers that argue investment skill is more prevalent than earlier papers suggest..