While also an individual portfolio asset in its own right, many investors such as JL Collins choose to keep it simple and put all of their money in a total stock market fund. Often written from a very US-centric perspective, that generally means the US stock market. Here you can see how it performs individually and observe how the ups and downs vary over the years. But the world is a big place, and individual countries have very different results. To see how the stock market varies by country, try out the same asset allocation in the different calculators.