What is a minimum balance?

A minimum balance is the amount of money you must keep in an account. It can apply in two different ways: to avoid a monthly fee, or to satisfy a bonus requirement. These two thresholds are separate, and it's easy to mix them up.

The first is the bonus requirement itself. Many bonuses ask you to deposit a certain amount and keep it there for a set period, usually 60 to 90 days. Something like deposit $10,000 and maintain it for 90 days. That money is tied up during that window, so it's worth thinking about what you're giving up by not having it somewhere else.

The second is the fee waiver threshold. Separately from the bonus, accounts often waive their monthly maintenance fee if you keep a minimum balance. Drop below it and the fee kicks in.

These two numbers are often different. You might need $10,000 sitting in the account to earn the bonus, but only $1,500 to keep the monthly fee at zero once you've collected it. Once the bonus posts, you can move most of the money out as long as you stay above the waiver threshold.

Keep both numbers written down somewhere. It's an easy thing to lose track of.