"Strength in numbers" pretty much sums up how investment funds work: A group of people (called shareholders) pool their money through a bank or financial firm. In doing so, they have more power to buy securities, like stocks and bonds, than they would as individuals. The fund's total value changes every day, and the shareholders' earnings go up or down depending on how the market is doing. But who actually decides what to buy? That's the job of an investment fund manager—to worry about the money so the shareholders don't have to. These highly paid financial whizzes strategize about spending. The goal, of course, is to get the greatest profit on the cash that's been invested. To guide their choices, fund managers watch the markets, keep up with current news (which can affect the economy), and research different companies. They might also meet with high-level investors and give interviews to publications like The New York Times or The Wall Street Journal. It's a challenging, high-pressure job that often requires long hours, but those who thrive in this career usually can't imagine doing anything else.