When you buy a share of a mutual fund or an ETF, you aren’t buying a tiny slice of one company. You instantly own a diversified basket of hundreds or even thousands of securities, managed by professionals. This chapter looks at the institutions that make this possible — from everyday mutual funds to secretive hedge funds, from venture capital that backs startups to specialised finance companies that help businesses manage cash. Along the way, we’ll see how they are structured, how they charge fees, and why they matter so much for channelling money from savers to the real economy.