Uninvested brokerage cash does not all work the same way. A broker may sweep it to one or more affiliated or unaffiliated banks, place it in a money-market mutual fund, leave it as a free credit balance, or offer a choice. The default can change by account type, balance, program eligibility, or broker policy.
The practical decision is not simply “cash sweep versus money-market fund.” Identify the exact destination for this account, then compare protection, net yield, access, settlement, minimums, and operational risk. Use the broker comparison framework to assess the full account rather than selecting a platform only for a temporary cash rate.
Bank sweep: deposit treatment with program rules
In a bank sweep, the brokerage moves eligible cash into deposit accounts at program banks. In the United States, eligible deposits may receive FDIC insurance within applicable limits and ownership categories. Coverage is not unlimited, and deposits already held directly or indirectly at the same bank generally matter when calculating the total.
Read the brokerage disclosure for participating banks, allocation order, interest tiers, and how cash returns for trading or withdrawal. Check whether the particular program offers bank-selection or exclusion options; do not assume every program lets you exclude a bank. Spreading cash among banks does not create extra coverage for deposits already held at the same bank in the same ownership category.
A hypothetical same-bank deposit example
Assume one individual owns USD 180,000 deposited directly at Bank A and USD 100,000 actually deposited at that same FDIC-insured bank through a brokerage sweep. Both are in the single-account ownership category, with no beneficiaries or other deposits in that category at Bank A. The amounts include accrued interest. Also assume the sweep meets FDIC pass-through requirements: the funds belong to the individual, the bank records disclose the agency relationship, and the relevant records identify the owner and ownership interest.
USD 180,000 + USD 100,000 = USD 280,000 at the same bank; USD 250,000 is insured and USD 30,000 exceeds the limit under these assumptions. The broker is an intermediary, not another ownership category. A program's advertised multi-bank capacity does not override this aggregation. The USD 30,000 is uninsured exposure, not a prediction that it will be lost. Different ownership arrangements or failed pass-through requirements can change the outcome; check the actual records and FDIC guidance.
Convenience can come with a low rate. Compare the current rate for the exact tier—not a headline from another account type—and calculate dollars using consistent assumptions. The worked example below uses invented inputs, not a current broker offer.
Money-market fund: an investment, not a bank deposit
A money-market mutual fund holds short-term debt instruments and seeks liquidity and a stable value, but it is a security. It is not a bank deposit and is not FDIC-insured. U.S. brokerage assets may be subject to SIPC customer-protection rules if the brokerage fails and assets are missing, but SIPC does not protect against a security losing value.
A quoted seven-day yield annualizes a recent period; it is not a guaranteed rate for the next year. Check the provider's definition: Fidelity, for example, defines its fund yield as earnings after expenses over the past seven days, annualized. If expenses are already reflected, do not subtract the expense ratio again. A gross rate before expenses and an already-net yield are different inputs. APY includes a compounding convention and is not automatically interchangeable with a seven-day yield.
Review the fund type, portfolio, expenses, minimums, purchase and redemption timing, cutoffs, and whether shares are sold automatically to cover trades or withdrawals. Government, prime, and tax-exempt money-market funds can have different risks and tax characteristics. SIPC treats money-market mutual funds as securities, not as insured bank deposits, and does not cover their market losses.
Settlement and access are part of return
Cash needed for an imminent securities purchase, bill, or withdrawal must be available when required. Some brokers treat an eligible fund as a settlement fund. Others require a separate purchase or sale. A late order, market holiday, settlement rule, or transfer hold can make apparently liquid money unavailable for the intended transaction.
Yield also changes. A bank can change a variable rate, and a money-market yield responds to its portfolio and expenses. Compare on the same date and create a review trigger instead of assuming today’s ranking will persist.
Where brokerage cash can sit
| Scenario | Best for | Upside | Main trade-off | Next step |
|---|---|---|---|---|
| Bank sweep | Automatic transactional cash | Potential deposit insurance within applicable limits | Rate may be materially below alternatives | Map every program bank and combined deposit |
| Money-market fund | Short-term investment cash with understood mechanics | Can offer competitive market-linked yield | Security risk and settlement mechanics apply | Read prospectus and broker liquidation rules |
| External bank account | Emergency reserves separate from investing | Clear household-liquidity role | Transfer delay between institutions | Test transfer timing before an emergency |
Work the comparison after tax and friction
For a deliberately simple one-year, constant-balance scenario:
E ≈ B × y_net − C_extra − T_est
- B is the balance held unchanged for the whole year, in USD.
- y_net is an assumed annual simple yield written as a decimal, after any fund expenses already incorporated. For example, 4% is 0.04.
- C_extra is additional annual dollar cost not already reflected in that yield, such as a separately charged account fee. Never deduct the same expense twice.
- T_est is an independently estimated annual tax amount in USD, not a tax rate. E is estimated earnings remaining after those additional costs and taxes.
Hypothetical example: keep USD 25,000 unchanged, assume a constant 4% annual simple yield already net of fund expenses, a separate USD 20 account charge, and USD 200 of estimated tax. The arithmetic is 25,000 × 0.04 − 20 − 200 = USD 780. Without the separate account charge, the same assumptions give USD 800; an expense ratio already inside the yield is not another deduction.
These invented rate and tax inputs are not a current offer, tax calculation, or promised income. The estimate assumes no reinvestment or compounding. A current seven-day yield does not establish the coming year's yield; changing balances, rates, or holding periods need a dated calculation instead of this constant-balance shortcut. For tax-exempt or Treasury-focused funds, confirm actual federal, state, and local treatment rather than assuming the entire distribution qualifies for an exemption.
Do not chase a small yield difference that creates transfer risk, repeated manual work, or loss of needed liquidity. Conversely, a stable five-figure balance can make a persistent rate gap worth addressing. Keep true household reserves aligned with the emergency-fund order of operations rather than treating brokerage buying power as a complete emergency plan.
When the cash belongs to a long-term portfolio, document its intended range in the investment policy. If it is waiting for a market prediction rather than a known expense or allocation rule, the larger issue may be investment discipline, not the cash product. The fund structure guide helps separate a money-market fund’s wrapper from its portfolio role.
Turn the page into action
Audit brokerage cash
- Find the exact sweep or free-credit destination for each account.
- Download the current program disclosure and fund prospectus where applicable.
- Record the exact balance tier, rate or seven-day yield, and expense treatment.
- Aggregate deposits at each bank across ownership-equivalent accounts.
- Confirm insurance or customer-protection limits without treating either as market-loss insurance.
- Test purchase, redemption, settlement, withdrawal, and automatic-liquidation mechanics.
- Use consistent balance, yield, additional-cost and tax assumptions; do not deduct expenses already included in the yield.
- Set a calendar or rate-change trigger for review.
Boundaries
This article uses U.S. bank-sweep, FDIC, money-market-fund, and SIPC concepts. Other jurisdictions use different protection and settlement systems. Program banks, yields, fund terms, and brokerage defaults can change, so verify the live disclosure and official rate on the decision date. For balances near protection limits, trust or business accounts, cross-border ownership, or cash needed for a fixed liability, obtain institution-specific guidance.
Evidence to action
Methods and evidence
Methods used
- One-year simple cash-earnings estimate
E ≈ B × y_net − C_extra − T_est
Next actions
Structured datasources.jsonformulas.jsonsystems.json
Evidence
Sources
- Don't Lose Interest: Managing Cash in Your Brokerage Account
finra-brokerage-cashFinancial Industry Regulatory AuthorityAccessedSeptember 1, 2026
- Cash Sweep Programs and Uninvested Cash
sec-cash-sweepU.S. Securities and Exchange Commission — Investor.govAccessedOctober 15, 2026
- Fidelity cash management: seven-day yield definition
fidelity-seven-day-yieldFidelity InvestmentsAccessedOctober 15, 2026
- Pass-through Deposit Insurance Coverage
fdic-pass-through-coverageFederal Deposit Insurance CorporationAccessedOctober 15, 2026
- Single Accounts
fdic-single-accountsFederal Deposit Insurance CorporationAccessedOctober 15, 2026
- Your Insured Deposits
fdic-insured-depositsFederal Deposit Insurance CorporationAccessedOctober 15, 2026
- How SIPC protects customers
sipc-investor-protectionSecurities Investor Protection CorporationAccessedOctober 15, 2026
Common questions
Frequently asked questions
Is a money-market mutual fund FDIC-insured?
No. A money-market mutual fund is a security and is not an FDIC-insured bank deposit. It may be held at a SIPC-member broker, but SIPC protection is different from deposit insurance and does not protect market value.
Why can a brokerage cash sweep pay less than market rates?
A firm chooses the sweep program and may receive economic benefit from it. The default can emphasize convenience or bank capacity rather than the highest available yield, so compare the disclosed rate with eligible alternatives.
Can I use a money-market fund immediately for a trade or withdrawal?
Operational treatment varies. Some brokers automatically liquidate designated funds; others require a sale, settlement, or manual transfer. Confirm purchase, redemption, debit, and settlement rules before relying on same-day access.
