Financialization of the global economy is now complete, thanks to the world's hyperactive Central Banks and the age of riskless recklessness they engendered.
Source: https://www.bloomberg.com/gadfly/articles/2017-12-04/98-750-067-000-000-reasons-to-be-scared-about-2018 The notable 'hockey stick' that is, dynamically reminiscent of the Bitcoin craze is now evident in the stock markets too, and it has zero parallels in the post-dot.com period. In fact, this is the highest global market capitalization level on record, as data from the World Bank augmented with current data through November 2017 shows:
You can think of the stratospheric rise in world equities valuations as a reflection of liquidity supply generated by the Central Banks since 2007. You can also think of it as a wealth buffer built up by the world's wealthy elites to protect themselves against potential future stagnation and political populism. You can equally think of it as a bubble.
Whichever way you spin these numbers, the rate of increase since 2015 has been simply unprecedented by historical standards, faster than the dot.com bubble and faster than the pre-GFC bubble.