Money Market Account vs. Money Market Fund: Don't Confuse Them

July 20, 2026

“Money market account” and “money market fund” sound like the same thing, get abbreviated the same way in casual conversation, and are frequently confused — but they’re regulated differently, insured differently, and carry different risk. This guide draws the line clearly before you rely on the money market calculator for the wrong product.

Money Market Account (MMA) — A Bank Deposit Account

A money market account is a deposit account offered by a bank or credit union. Per CFPB guidance, it’s insured by the FDIC (or NCUA for credit unions) up to $250,000 per depositor, per institution, per ownership category — identical protection to a regular savings account or CD. This is the product the money market calculator is built to project: principal plus contributions, compounding at a single or tiered APY.

Money Market Fund (MMF) — An Investment Product

A money market fund is a type of mutual fund, regulated by the SEC rather than a banking regulator, that invests in short-term, low-risk debt instruments. It is not FDIC or NCUA insured. Per the SEC’s own investor bulletin, money market funds are generally designed to maintain a stable $1.00 share price, but in rare circumstances a fund can “break the buck” — its share price drops below that $1.00 target, meaning investors can actually lose principal, something that cannot happen to an FDIC-insured deposit account within insurance limits.

Side-by-Side Comparison

	Money Market Account (MMA)	Money Market Fund (MMF)
What it is	Bank/credit union deposit account	Mutual fund (investment product)
Regulator	FDIC / NCUA (banking regulators)	SEC (securities regulator)
Insured?	Yes, up to $250,000	No
Can lose principal?	No, within insurance limits	Rarely, but yes (“breaking the buck”)
Where it’s held	A bank or credit union account	A brokerage account or fund company
What this calculator models	This product	Not this product

How to Tell Which One You’re Being Offered

Check where the account is opened. A product opened directly through a bank or credit union, with an account number and routing number, is almost always an MMA. A product purchased through a brokerage account alongside stocks and ETFs is very likely an MMF (sometimes called a “sweep” fund or a cash management fund).
Look for the word “FDIC-insured” or “NCUA-insured” explicitly stated. If a product’s disclosures instead mention it’s “not a deposit,” “not FDIC insured,” or “may lose value,” that’s a fund, not a bank account, regardless of what it’s casually called.
Check the rate structure. A tiered APY based on balance thresholds — the specific feature the money market calculator models — is a common MMA structure. Funds typically quote a single yield that fluctuates with the underlying short-term debt market rather than a balance-tiered rate.

Why This Distinction Matters for Using This Calculator

The money market calculator’s compounding formula assumes a fixed or tiered APY applied to a principal balance the way a bank deposit account works — it does not model the variable, market-driven yield of a fund, nor the (rare but real) possibility of a fund’s share price dropping. Using this calculator to project a money market fund’s growth risks treating an investment product’s return as if it carried deposit-account guarantees it doesn’t actually have.

Bottom Line

If federal deposit insurance matters to you — meaning you want a hard guarantee your principal is protected up to $250,000 — confirm you’re opening an FDIC- or NCUA-insured money market account, not a money market fund, before relying on the money market calculator’s projections. See choosing between a money market account, HYSA, and CD for how MMAs compare to other insured deposit options once that distinction is confirmed, and the money market account terms glossary for the FDIC, NCUA, and Reg D vocabulary that separates the two products.