Is there evidence of a US capital glut?
Core argument: The marginal product of US capital rose from 5.84% in the 2000s to 6.42% in the 2010s, and the US capital-output ratio remains close to its postwar average.
There has been no major increase in the US capital-output ratio, nor has there been a major decline in the US marginal product of capital – the economy’s real return to capital. The US capital-output ratio remains close to its postwar average and capital’s real return has remained roughly constant -- around 6%. During the 2000s the marginal product of U.S. capital (MPK) was a healthy 5.84%. In the 2010s it was even higher at 6.42%. The market return to capital would show a decline if there were a capital glut and investors expected lower rates of return, It shows no such decline. The market return to capital’s real return averaged 5.52% between 1950 and 1989. Btw 1990 and 2019 it averaged 6.95. Hence, the broadest market-based real return data shows a rise, not a fall in returns in the recent decades during which capital has allegedly been in vast oversupply. The real return to US wealth between 2010 and 2019 averaged 8.25% – the highest average return of any postwar decade.




