Once Economics is researched you have the ability to build the stock exchange. At this point you have the ability to invest in a certain country/empire. Here's how this works: You make money by investing gold in a foreign country that is growing or has potential to grow. What is growth? It could be measured by available empty tiles surrounding current cities. Also, by available land left in immediate area for additional cities to be settled. Growth would be measured by improving tiles with workers and building districts, buildings, and wonders. We could consider growth for population as well. Another way of placing value on the stock would be +/- the country's science progress, gold per turn, and culture progress average to the rest of the world. Plus Normal, Golden, Dark and Heroic ages can have a major stock value increase or decrease. By making the correct investment in the world community you will stand to make boatloads of cash as you sell your shares/investment in a particular empire/country. But beware! If a certain country would have disasters, war, and bankruptcy this would incur a drop in share price/stock value and even resulting in a crash. Would you panic and sell your shares? Or stick it out and hope the country/empire could recover. War could be boon or bust. If a empire/country takes over cities or another empire/country entirely then the winner would open up potential for further growth and higher stock price. LIkewise the loser would suffer a major stock crash and the stock price would go to zero if defeated. How does one's country/empire make money from it's own stock? After you build your stock exchange you have the ability to list your country on the exchange. You simply issue a certain amount of shares at $X price, once other countries/empires/city states buy those shares with gold, that cash goes into your treasury and it's free to use as you please. Will you put your investor's money to good use? Gamble with a war? Or invest in another country? The choice is yours.