While reading a Bloomberg article on how the default in Greece caused a loss of $1 trillion dollar in the global equity market, a question came into my mind, what is the total value of the stock market? In other words, what is the sum of the market capitalization of all listed stocks?

I researched this question on the Internet and nobody seems to have answered it before, so I decided to do it myself.

Here’s how I did it: I created a script that will go through all the currently listed stocks in both the NYSE and the NASDAQ and get the market cap of each and every stock. I then summed all the market caps, and here’s the number I got: $23,346,980,800,000. So, the total value of the US stock market (NYSE and NASDAQ) is $23.34 trillion.

Now, a few weeks ago, I have generated a list with the top 100 companies by market cap, so, what I want to know right now is how much do these companies constitute of the total worth of the stock market. If you look at the aforementioned list, the combined market cap of these companies is $11.71 trillion, which means that the top 100 listed company by market cap represent 50.17% of the total stock market value.