Reading this Ed Yardeni summary of Q1 S&P earnings. Overall US non-financial corp margins peaked in the 2012-2014 period and have fallen since. $'s of profit have more or less gone sideways as US GDP grew. Obviously the S&P is buying back shares at a rate of 1.7% a year recently, using 54% of their Free Cash Flow, according to Factset.
Ed describes a drawn-out cycle that can continue for a few more years, this had been my view as well, last year, but the slowdown in many data points since Trump was elected now gives more cause for near term concern. In particular, many of the populist policies being enacted in the US and Europe will pressure corporate margins in favour of investment, transfers and wages.