Pressing for Yet More

On December 6, the S&P 500 set the most extreme level of valuations on record, exceeding both the 1929 and 2000 market peaks on measures that we find best-correlated with actual, subsequent 10-12 year S&P 500 total returns across a century of market cycles.

Reliable valuation measures are enormously informative about both long-term investment returns and the potential depth of market losses over the completion of any given market cycle. At the same time, valuations are of strikingly little use in projecting market outcomes over shorter segments of the market cycle. Investor psychology – the desire to speculate, or the aversion to risk – has a much stronger impact, which is why we also have to attend to factors including market internals, sentiment, short-term overextension / compression, and monetary policy (while unfavorable market internals dominate monetary easing, favorable internals amplify it).

Amid the untethered enthusiasm about artificial intelligence, and prospects for deregulation and lower corporate taxes, it’s worth repeating that despite all the society-changing innovations of the past 20-30 years, both GDP and S&P 500 Index revenues (which include the impact of stock buybacks) have grown at an average rate of only about 4.5% annually. That’s slower, not faster, than the growth rate during the preceding half-century.