In this question I'm using the Vanguard Total Stock Market Index Fund(VTSMIF), which for my purposes I find to be a sufficient indicator of the US market as a whole. (Please explain why this isn't an accurate indicator is that's the case.) I'm also using strictly the M1 money supply, as it most closely correlates to the stock market(and another source), and also because the increases in M2, M3, and MZM have been comparable over the time frame referenced.
In February, 2020 the VTSMIF was at $\\\$164.96$. At that time the M1 money supply was roughly $\\\$4,003,000,000,000.$ As of June 2020 the M1 money supply had been increased to $\\\$5,209,900,000,000.$ That's a roughly 30% increase in the money supply. At the same time, the VTSMIF had only recovered to $\\\$154.75$, or a ~6% decrease.
So we're looking at a 30% increase in money supply that, typically, directly ties to stock prices. I also don't think population increase in the time frame is a material factor, but please correct me if I'm wrong. Even if we assume no further increase in M1 money supply since June, and use today's VTSMIF value of (currently) %\$171.21$, we're looking at a ~4% increase in value, when historically we'd expect an increase in value closer to the increase in money supply.
I know there are myriad factors in play, these are unprecedented economic times, etc etc. But is it incorrect to say that despite slight upwards movement in USD value since February 2020, the stock market has actually lost a significant amount of real value, due to the drastic increases in money supply over the time frame? Assuming it's correct to state that, how would one calculate the actual loss of value?