What's the difference between a money market fund, a high-yield savings account, and a CD for holding cash?

All three are low-risk homes for cash, but they trade off access and rate differently. A high-yield savings account is fully liquid and FDIC-insured, with a variable rate that can change anytime — ideal for your front-line emergency fund. A money market fund is a brokerage investment (not a bank deposit, so not FDIC-insured) that holds very short-term, high-quality securities; it's typically quite stable, often pays a competitive yield, and stays liquid, but carries a sliver more risk than insured deposits. A CD locks your money for a set term in exchange for a fixed rate, and you pay a penalty for early withdrawal — best for cash you're confident you won't need until the term ends. Match the tool to the timeline: instant-access savings for emergencies, CDs or money market funds for cash with a known horizon.