Market cap is a great representation of what a company is worth. As you pointed out, market cap is share price x outstanding shares. For the case of Apple, it

Market cap is a great representation of what a company is worth. As you pointed out, market cap is share price x outstanding shares. For the case of Apple, it's $1 trillion, which is minimum amount you'd need to pay to buy out Apple. Issuing more stocks or initiating buy back will change stock price, but it won't impact the total market cap. Stock price already reflects fair value of the company's earnings performance and potential.