Paul Morigi/Getty Images The Buffett Indicator is the ratio of a country’s stock market capitalization to the overall GDP of the country. If the stock market is below 50% of the GDP, it is too low. Between 75% and 90%, the market is about right. Above 115%, it is overvalued on a relative basis. In late 2017 the market is over 130% of the GDP. It can help investors identify countries and sectors with undervalued stock markets. Warren Buffett is one of the most esteemed and revered investors of all time. His investing prowess has led him to become the richest person in the world (at times) and one of the top 5 today.