In this work of effective demand, the profit rate can be seen as a function of labor share and unemployment.
Basic equation based on...
Profit rate limit for optimization of capacity utilization, United States = labor share index * 0.76 / (1 - unemployment rate)
The dynamics behind this equation are not going to be discussed in this post.
The terms of the regression... (link to FRED data)
Annual corporate profit rate
National income: Corporate profits with IVA and CCAdj: Profits after tax with IVA and CCAdj, Billions of Dollars, Not Seasonally Adjusted / Gross National Product, Billions of Dollars, Not Seasonally Adjusted
(1 - annual unemployment rate/100)
Annual nonfarm Business Sector: Labor Share, Index 2009=100, Seasonally Adjusted /100 * 0.76
Regression from 1948 to 2015
The regression line is blue. The general tendency comes out over almost 7 decades.
Regression from 1991 to 2015
The blue regression line tightens up to the profit rate line after 1991. The adjusted R Square is already over 90%. P-values are within limit.
Shorter time periods for the regression increase the effect of labor share and decrease the effect from unemployment.
I am still reviewing these regressions. Monetary policy may have a place.