“Apple is worth $2,000,000,000,000. That is a lot of money” said Anthony Pompliano on Twitter the other day. Dave Collum promptly corrected him: “priced at.” This is a very important and warranted distinction. We talk about the market capitalizations of companies all the time, but less often we think about what it actually implies.
For Every Buyer there is a Seller
The current price of a publicly traded stock is the most recent point where the most willing seller and most eager buyer matched. So when Apple stocks ended a trading day at $498, the last buyer and seller that were matched were willing to do business for that price. For someone to buy, someone also has to sell.
But the market price only gives us some information about the marginal sellers and buyers. One an average day, somewhere between 100 to 200 million shares of Apple stock will change hands. That’s a lot of shares. On particularly busy days, this will exceed 300 million. On a slow day, however, as little as 50 million shares will change hands. But Apple has 4.35 billion shares outstanding. So, even on the most hectic days, less than 7% of the outstanding shares will change hands.
The 7% figures is likely deceptive as high frequency trading and other forms of day trading and market making might overstate the fact that the majority of stockholders will not sell on a given day.
Therefore, the market cap and stock price of a company will tell you where it is priced at by the market. it won’t tell you where the stock is valued at by the market.
How to Value Stuff 