When a bonus requires a balance to sit still for 90 days, the question is where to keep it. Money market accounts, savings accounts and money market funds are three different things, and only two of them are bank deposits.
The three products, plainly
- Savings account — a bank deposit, federally insured, variable rate, limited or no cheque access.
- Money market deposit account (MMDA) — also a bank deposit, also federally insured, usually with limited cheque-writing or a debit card attached. Often requires a higher minimum balance for the best rate.
- Money market fund — an investment, held at a broker, not a bank deposit and not federally insured. It aims to hold a stable value but is not guaranteed to.
The naming is genuinely confusing, and the distinction matters most when you are parking a large qualifying balance.
Insurance is the first filter
Bank deposits are insured by the FDIC, and credit union deposits by the NCUA, up to the standard limit per depositor, per institution, per ownership category. A money market fund sits outside that entirely; it may carry brokerage protection against firm failure, which is not the same as protection against the fund losing value.
If the whole point is holding cash safely for a bonus period, an insured deposit account is the straightforward choice.
Tiered rates and the balance trap
MMDAs commonly pay tiered rates, where the headline APY applies only above a threshold. Fall below it and the rate can drop sharply — and the same dip may also break the bonus balance requirement and trigger a monthly fee. Three conditions, one balance, all failing together.
Keep a buffer above the highest relevant threshold rather than sitting exactly on it.
Transaction limits
The old federal cap of six withdrawals per month on savings and money market accounts is no longer mandatory, but many banks kept their own version and charge a fee for exceeding it. If the account is holding a bonus balance you were not going to touch anyway, this rarely matters — but check before using it as an everyday account.
Choosing for a bonus period
- Confirm the account type named in the offer — some bonuses specify savings and exclude money market, or vice versa.
- Check whether the qualifying balance is tested daily or on average.
- Check the rate tier thresholds and set your balance above the nearest one.
- Confirm the fee waiver condition and whether it is the same balance.
- Confirm the deposit is insured and within limits.
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