The total value of all the stock markets in the world amounts to less than $50 trillion, according to the World Federation of Exchanges.Try as we might to salvage the residential real estate market, it's at best worth $23 trillion in the U.S. We're struggling to save the stock market, but that's valued at less than $15 trillion. And we hope to keep the entire U.S. economy from collapsing, yet gross domestic product stands at $14.2 trillion