Buffett acknowledged that his metric was a simple one and thus had "limitations", however the underlying theoretical basis for the indicator, particularly in the US, is considered reasonable. GDP captures effects where a given industry's margins increase materially for a period, but the effect of reduced wages and costs, dampening margins in other industries. The indicator has also been advocated for its ability to reduce the effects of "aggressive accounting" or "adjusted profits", that distort the value of corporate profits in the
price–earnings ratio or
EV/EBITDA ratio metrics; and that it is not affected by share buybacks (which don't affect aggregate corporate profits). The Buffett indicator has also been calculated for industries (but also noting that it is not relevant for
cross industry valuation comparison).
Trending There is evidence that the Buffett indicator has trended upwards over time, particularly post 1995, and the lows registered in 2009 would have registered as average readings from the 1950–1995 era. Reasons proposed include that GDP might not capture all the overseas profits of US multinationals (e.g. use of
tax havens or
tax structures by large US technology and life sciences multinationals), or that the profitability of US companies has structurally increased (e.g. due to increased concentration of technology companies), thus justifying a higher ratio; although that may also revert over time. Other commentators have highlighted that the omission by metric of corporate debt, could also be having an effect. ==Formula==