Thought experiment: suppose company C does a small IPO. I'm rich and buy all their offering.

Scenario 1: I hold all the stock for decades until I die. Under your terminology, I am the sole "investor". Fine.

Scenario 2: 1 millisecond after my purchase I sell everything I bought in the IPO to thousands of market participants. Under your terminology they are not "investors". I can't be an investor either, since I hold no more of the stock. Does the company no longer have investors?