I suspect that for a lot of people here the answer to "are you a millionaire" would depend on how you're valuing the stock they own.
(I think that's relevant since HNW definitions exclude the value of their primary residence. [1])
[1]High-net-worth individual (HNWI) is a term used by some segments of the financial services industry to designate persons whose investible assets (such as stocks and bonds) exceed a given amount. Typically, these individuals are defined as holding financial assets (excluding their primary residence) with a value greater than US$1 million.[1][2][3]) https://en.wikipedia.org/wiki/High-net-worth_individual