How much real value has the stock market lost since Feb. 2020?
Increases in the money supply do not affect the real value of investments unless they lead to inflationary increases in the (quality-adjusted) prices of goods and services. Which this increase has not done. If you choose to measure the value of your investment as the proportion of the M1 money supply that it represents then sure, it has been devalued, but that’s a rather pointless and futile way to measure the value of investments.