This time it’s some of the most respected minds in the world propagating theories of a “new era” for risk assets. Jeremy Grantham recently wrote a piece arguing that both equity valuations and profit margins have possibly reached a new, higher plateau:
Jeremy Grantham on why stock prices can remain high..
So, to summarize, stock prices are held up by abnormal profit margins, which in turn are produced mainly by lower real rates, the benefits of which are not competed away because of increased monopoly power, etc. What, we might ask, will it take to break this chain? Any answer, I think, must start with an increase in real rates . Last fall, a hundred other commentators and I offered many reasons for the lower rates. The problem for explaining or predicting future higher rates is that all the influences on rates seem long term or even very long term. One of the most plausible reasons, for example, is the aging of the populations of the developed world and China, which produces more desperate 50-yearolds saving for retirement and fewer 30-year-olds spending everything they earn or can borrow. This results, on the margin, in a lowered demand for capital and hence lower real rates. We can probably agree that this reason will take a few decades to fade away, not the usual seven-year average regression period for financial ratios.
Any effect of lower population growth rates is likely to take even longer. No one seems sure what is causing lower productivity growth or what role it has in lower rates, but it would take some very unexpected good fortune to have productivity accelerate enough to drive rates upward in the near term. Income inequality that may be helping to keep growth and rates lower will, unfortunately, in my opinion, also take decades to move materially unless we have a very unexpected near revolution in politics.