This is available directly from Wilshire (links to all data sources below), with monthly data starting in 1971, and daily measures beginning in 1980. The most common measurement of the aggregate value of the US stock market is the Wilshire 5000. To calculate the ratio, we need to get data for both metrics: Total Market Value and GDP. (Buffett has since walked back those comments, hesitating to endorse any single measure as either comprehensive or consistent over time, but this ratio remains credited to his name). Named after Warren Buffett, who called the ratio 'the best single measure of where valuations stand at any given moment'. The Buffett Indicator is the ratio of total US stock market value divided by GDP.
