Warren Buffett's own measurement of success is not been that impressive of the past 3 to 4 years, compared to you S&P. This remains my top holding and I am now finally starting to wonder if it has lost its mojo.
The problem is that its not really a fair comparison anymore, particularly when theres a strong bull market. Since berkshire has become largely an operating business, i think you could argue that s&ps book value is a more proper benchmark although that can get thrown off too by a strong market. Berkshire book value growth over last 3 years: 11.67% annually. S&p book value growth: 6.87% growth plus roughly 2% annual dividends