Money Market Account Terms Glossary: APY, Reg D & FDIC

July 20, 2026

A money market account statement uses a handful of terms that don’t show up on a plain savings account. Here’s what they mean for the money market calculator.

APY (Annual Percentage Yield)

The rate of return including the effect of compounding, as opposed to APR, which doesn’t account for compounding frequency. Money market accounts advertise and pay APY, which is exactly what the money market calculator uses in its compounding formula.

Tiered Rate / Blended APY

A rate structure, common on money market accounts and rare on plain savings accounts, where different portions of a balance earn different APYs depending on which balance tier they fall into — similar to how tax brackets work. The blended APY is the single effective rate that results once all tiers are combined. See the money market calculator for a full worked example.

Regulation D

The Federal Reserve regulation that historically limited “convenient” transfers and withdrawals from savings and money market accounts to six per statement cycle. An interim final rule effective April 24, 2020 removed this as a federal requirement — it’s no longer the law, though many banks kept a similar limit as their own account policy. See do money market accounts still limit withdrawals? for how this affects account choice today.

FDIC / NCUA Insurance

Federal deposit insurance protecting money market account balances up to $250,000 per depositor, per insured institution, per ownership category (individual, joint, certain retirement accounts, etc. each count separately) — provided under FDIC for banks or NCUA for credit unions. This is the same protection level as a savings account or CD.

Money Market Account (MMA) vs. Money Market Fund (MMF)

Two entirely different products that share a confusingly similar name. An MMA is a bank deposit account, FDIC/NCUA-insured, and covered by the money market calculator’s compounding math. A money market fund (MMF) is an investment product (a type of mutual fund) regulated by the SEC, not FDIC-insured, and — while historically very stable — can in rare cases “break the buck,” meaning its share price drops below the usual $1.00 target. See money market account vs. money market fund: don’t confuse them for the full distinction.

Minimum Balance Requirement

A bank-specific threshold, separate from rate tiers, that may be required just to open the account or to avoid a monthly maintenance fee — distinct from the (often much higher) balance needed to unlock a tiered account’s top advertised APY.

Excess Transaction Fee

A fee some banks still charge if an account exceeds that bank’s own self-imposed transaction limit (commonly still six per month, even though it’s no longer federally mandated under Regulation D).

Using This Glossary

Match these terms against your own account terms, then use the money market calculator to project growth under a single or tiered APY structure. See common money market calculation mistakes for how misreading these terms commonly leads to an inflated growth projection.