Say you buy 100 shares of Apple (AAPL) at $150 each. Later, supply chain issues arise or a new Apple product underperforms causing investors to lose confidence, which pushes the stock price to $100 per share. It's not really a $50 per share loss. Rather, it's a reflection of what investors are now willing to pay for Apple shares—the way a new car's value depreciates—the vehicle hasn't changed, but its market value does.
Learning to understand!