This is basically Warren Buffett's conception of a stock: a bond with a variable interest rate. It gets easier when you think of a share as a fractional claim

This is basically Warren Buffett's conception of a stock: a bond with a variable interest rate. It gets easier when you think of a share as a fractional claim on a cashflow (profits - what's "left over"). Bondholders are generally promised a specific amount upfront. Stockholders get what's left over -- the amount of that is anyone's guess. It gets pretty abstracted when you start talking about firms that don't pay out profits but the basic idea is sound.