Direct answer: A bank savings account is FDIC-insured up to $250,000 per depositor per institution; a money market fund is not FDIC-insured but typically holds extremely short-duration, high-quality debt and aims to maintain a $1.00 NAV. Money market funds typically offer higher yields than savings accounts because banks retain a spread on deposits; money market funds pass through the near-full short-term rate. The choice is a safety-versus-yield trade-off that depends heavily on account size relative to FDIC limits.
Money Market Fund or Bank Savings Account? What Actually Changes
Key Takeaways
- FDIC insurance is a federal guarantee; if the bank fails, depositors receive their insured balance. A money market fund breaking the buck (NAV falling below $1.00) is possible but rare; it happened to the Reserve Primary Fund in 2008 and triggered a government guarantee program.
- Government money market funds (holding only Treasury and agency securities) are structurally safer than prime money market funds (holding commercial paper and bank CDs) but typically yield slightly less.
- 2023 reform rules require institutional prime money market funds to implement redemption gates and liquidity fees when liquid assets fall below certain thresholds; retail prime funds have similar mechanisms.
- For amounts under $250,000 where FDIC coverage applies, the safety comparison is roughly equivalent in practice; yield difference drives the choice.
- For amounts over $250,000, comparing Treasury-only money market funds to bank savings requires analyzing specific risks: bank failure recovery timeline, fund NAV stability, and practical redemption speed.
What FDIC Insurance Actually Covers
FDIC insurance is a federal guarantee backed by the full faith and credit of the U.S. government. If an FDIC-member bank fails, the FDIC takes over, and insured depositors receive their principal plus accrued interest up to $250,000 per depositor per institution per account ownership category within a few business days. In the 2008 financial crisis, no insured depositor lost a dollar. The key limitations: the $250,000 per-institution cap means large balances at a single bank can have uninsured exposure, and the 'per institution' rule means spreading across multiple banks multiplies coverage.
How Money Market Fund Safety Works
A money market fund is not a bank deposit; it is a mutual fund that invests in short-duration, high-quality debt instruments. A government money market fund holds only Treasury bills, Treasury notes maturing soon, and repurchase agreements backed by Treasuries; these instruments have the credit quality of the U.S. government. A prime money market fund holds commercial paper, certificates of deposit from banks, and other short-term corporate debt; these carry credit risk, which is why prime funds yielded slightly more than government funds before the 2008 crisis. The safety mechanism for government money market funds is nearly equivalent to FDIC insurance in practice, because the underlying holdings are guaranteed by the U.S. Treasury.
The Yield Difference and Why It Exists
Bank savings accounts (especially at traditional large banks) often pay yields significantly below the Federal Funds Rate because banks can fund most lending at low deposit rates without losing depositors to alternatives. High-yield savings accounts at online banks (Marcus, Ally, Marcus by Goldman Sachs) typically offer rates closer to the Fed Funds Rate. Money market funds pass through the near-full short-term rate because they compete on yield; their management fees (0.01% to 0.20% per year on government funds) are the primary cost, and the remaining yield accrues to investors. In a 5% rate environment, the difference between a big-bank savings account (0.5%) and a government money market fund (4.8%) is 4.3 percentage points, which compounds quickly on large balances.
Decision Framework
Use bank savings accounts for: amounts under $250,000 where FDIC insurance provides peace of mind, very short-term use (days to weeks) where the marginal yield difference is small, and institutional access where a money market sweep account is automatically managed. Use government money market funds for: amounts over $250,000 where a single bank cannot cover the balance without multi-bank management, maximizing yield on cash reserves in a brokerage account, and situations where the higher yield compounds meaningfully (6+ month horizon). Use prime money market funds only with full understanding of the slightly higher credit risk versus government funds; the yield premium is usually small (0.05% to 0.20%).
Frequently Asked Questions
Has a money market fund ever broken the buck?
Yes. The Reserve Primary Fund broke the buck on September 16, 2008, after taking losses on Lehman Brothers commercial paper; its NAV fell to $0.97. This triggered a run on money market funds industry-wide. The Treasury Department issued a temporary guarantee program for money market funds within 24 hours. Since the 2008 crisis and subsequent regulatory reforms (2010 and 2014), no money market fund has broken the buck in the retail market.
What are 'redemption gates' on money market funds?
Under SEC Rule 2a-7, certain money market funds can temporarily restrict or delay redemptions (gates) when the fund's liquid assets fall below threshold levels. These mechanisms are designed to prevent a run by slowing redemptions during stress. The 2023 updates to Rule 2a-7 modified these provisions. Before investing, review the fund prospectus for current gate and fee provisions, particularly for institutional prime funds.
Should I move my emergency fund from a savings account to a money market fund?
For most individuals with emergency funds under $250,000, the FDIC protection of a high-yield bank savings account provides equivalent safety with minimal friction, and the yield from top online bank savings rates is often competitive with retail money market funds. For cash reserves above $250,000 per institution, or for investors managing large cash positions in brokerage accounts, a government money market fund often provides better yield with comparable practical safety.