A brokerage cash sweep is a routing instruction, not one universal product. Depending on the program, idle cash may become a deposit at one or more banks, shares of a money market mutual fund, or a cash balance held by the broker. Those choices can look similar on an account screen while carrying different legal protections, return measures and trading-availability rules.
The first question is therefore not “What is the sweep rate?” It is “What does my cash become?” The program disclosure and account statement should identify the destination. Rates and fund yields change, so this guide focuses on the structure that remains useful when rates move.
Three Ways Brokerage Cash Can Be Held
1. Bank deposit sweep
The broker or its clearing firm moves eligible cash into a deposit account at a participating FDIC-insured bank. The bank owes the deposit balance; the brokerage is the intermediary that administers the sweep. The FDIC explains that pass-through coverage can apply when a third party places funds at an insured bank for the actual owner, provided the ownership, disclosure and recordkeeping requirements are satisfied.
Pass-through coverage is not a separate ownership category. A customer’s swept balance is added to the customer’s other deposits in the same ownership category at the same bank. The standard limit is generally $250,000 per depositor, per insured bank, per ownership category. A program that uses several banks may create more capacity, but the actual amount depends on the program’s current bank list, the customer’s existing deposits at each bank and whether pass-through requirements are met. There is no safe universal multiplier such as “four banks equals $1 million.”
2. Money market mutual fund
A money market fund is a mutual fund that owns short-term debt instruments, cash and cash equivalents. It is a security, not a bank deposit, and it is not FDIC-insured. The SEC’s money market fund bulletin says fund yields change with short-term interest rates and explains that even stable-NAV funds can lose value. Most retail and government money market funds seek a stable $1 share price, while institutional prime and institutional tax-exempt funds use a floating NAV.
Redemption and trading access depend on the fund and broker. Investors can generally redeem money market fund shares on a business day, but whether a broker automatically sells shares to settle a trade, and when proceeds become available, are program-specific. Some funds may also impose liquidity fees under the conditions described in their disclosures.
3. Cash held by the broker
A brokerage can also carry a free credit balance: cash owed to the customer and held for purchasing securities. This is different from a deposit swept to a bank and different from fund shares. The account agreement and statement should identify which arrangement applies.
FDIC and SIPC Protect Different Failure Modes
FDIC deposit insurance addresses failure of an insured bank, subject to coverage limits, ownership categories, aggregation and recordkeeping. It does not insure mutual fund shares or protect a brokerage firm.
SIPC addresses missing customer property when a SIPC-member brokerage fails and enters a protected liquidation. SIPC lists money market mutual funds as securities. The overall statutory limit is $500,000 per customer in each separate capacity, including a $250,000 limit for claims for cash. Money market fund shares count as securities rather than cash for that sublimit.
SIPC is not investment insurance. It does not reimburse a decline in a fund’s NAV, a lower yield, or other market loss. The SEC’s SIPC protection bulletin also makes the sweep distinction explicit: cash held at the broker for securities transactions and money market fund shares may be covered by SIPC, while a bank-sweep deposit is held outside the brokerage and instead relies on applicable banking law and FDIC coverage.
| Cash destination | What the customer owns | Primary failure protection | Main caveat |
|---|---|---|---|
| Bank deposit sweep | Deposit at a program bank | FDIC, if eligible and within applicable limits | Same-bank deposits in the same ownership category aggregate; pass-through records must qualify |
| Money market fund | Mutual fund shares | SIPC customer-property protection if the member broker fails | No FDIC insurance and no SIPC protection against fund losses |
| Broker free credit balance | Cash claim against the broker for securities activity | Potential SIPC cash protection if the member broker fails | The $250,000 cash sublimit is part of the $500,000 overall limit |
| Treasury bill held in brokerage | U.S. Treasury security | U.S. government obligation; SIPC custody protection may apply at a failed member broker | Selling before maturity can produce a gain or loss; settlement and transaction terms vary |
A Hypothetical Cash-Drag Calculation
The arithmetic can show why the election matters, but it should not be mistaken for a quote. Assume, only for illustration, that $100,000 remains unchanged for one year, one option earns 0.35% and another earns 4.75%, with no compounding, fees or taxes:
- $100,000 × 0.35% = $350 of hypothetical annual income.
- $100,000 × 4.75% = $4,750 of hypothetical annual income.
- The hypothetical difference is $4,400.
These are deliberately hypothetical inputs, not current brokerage, bank, fund or Treasury rates. For an actual comparison, use the bank sweep’s stated annual percentage yield, the fund’s current seven-day yield and expense ratio, or a Treasury bill’s investment rate for the same observation date. Confirm whether each figure is net of expenses and whether it compounds.
Where Treasury Bills Fit
A Treasury bill is neither a sweep deposit nor a money market fund. TreasuryDirect says bills are sold at a discount or at par, pay face value at maturity and can be sold before maturity. Holding to maturity avoids the uncertainty of a secondary-market sale price; selling early can create a gain or loss as market rates change.
Direct Treasury interest is subject to federal income tax but exempt from state and local income taxes, according to IRS Publication 550. A money market fund’s state-tax treatment is less automatic: it can depend on the fund’s holdings, the investor’s state and the fund’s annual tax reporting. A fund with Treasury holdings should not be described as universally or fully state-tax exempt without checking those documents. ECMSource’s savings account versus Treasury bill guide explains the tax and maturity tradeoffs in more detail.
A Six-Question Sweep Review
- What is the legal destination? Identify a bank deposit, money market fund or broker cash balance by name.
- Which institution owes the balance? For a bank sweep, review the current participating-bank list and priority order.
- What already sits at the same bank? Combine deposits held in the same ownership category when evaluating the FDIC limit.
- How is the return quoted? Compare the bank APY, fund seven-day yield after expenses and Treasury investment rate on the same date.
- How does cash become available for a trade or withdrawal? Check automatic liquidation, cutoff times, settlement and any redemption fee provisions.
- Can the default change? Some brokers offer several core choices; others require a manual purchase. Use the current account agreement rather than assuming another broker’s process applies.
Sources
- FDIC — Pass-Through Deposit Insurance Coverage
- SIPC — What SIPC Protects
- SEC Investor.gov — SIPC Protection Basics
- SEC Investor.gov — Money Market Funds Investor Bulletin
- TreasuryDirect — Treasury Bills
- IRS Publication 550 — U.S. Treasury Interest
Correction, September 21, 2026: The original version presented unsourced yield ranges and program-specific sweep mechanics as general facts, conflated the SIPC cash sublimit with protection for money market fund shares, and understated early-sale risk for Treasury bills. The comparison, protection language, tax discussion and examples have been rewritten from primary sources. All percentages in the example are hypothetical.
Disclosure: This article is for informational and educational purposes only and is not investment, tax or legal advice.