Brokerage cash sweep — where your idle cash actually sits

The “cash sweep” at a brokerage account is the policy that determines where your uninvested cash sits between trades. It is one of the most invisible structural choices in personal investing — for most account holders, the broker chose it via the default option at account opening, and few revisit the choice. That default can cost a household $500 to $5,000 per year in forgone interest on idle cash, depending on the broker and the balance. This guide walks through what the cash sweep actually is, how the four major US brokers handle it differently, the multi-percentage-point yield gap that compounds quietly across years, and the specific actions to recover that yield without changing brokers.

What “cash sweep” actually means

When you sell a security at a brokerage, the proceeds become cash sitting in your account, available to reinvest. When dividends pay or interest accrues, they also become cash. When you deposit money from your bank, it lands in the account as cash. In each case, the broker has to put that cash somewhere — earning interest in some manner, custodied with some protection.

Different brokers handle this differently:

• Money market fund sweep — the cash is held as shares of a money market mutual fund (an SEC-regulated 2a-7 fund holding short-term Treasuries, commercial paper, or other short-duration assets). The fund pays a daily-accruing dividend (the “7-day yield”) that flows back to the account holder. The fund is a security held in your brokerage account; SIPC insurance covers it up to $500K combined securities limit (no separate cash sublimit applies because the MMF is treated as security).

• Bank deposit sweep — the cash is moved to one or more partner banks (often affiliated banks owned by the broker’s parent) where it sits as a bank deposit. The bank pays interest (typically at a “transactional account” rate set by the bank, NOT the prevailing market rate for short-term cash). The deposit gets FDIC insurance up to $250K per depositor per partner bank.

• Hybrid or settlement-fund — some brokers (Vanguard) use a “settlement fund” that is functionally an MMF but is held as a separate position rather than auto-swept from cash. The user sees a fund balance, not a “cash” line.

The choice of mechanism is the broker’s decision, and the default at account opening determines what most account holders end up with. The mechanism difference is roughly invisible to the account holder but has a 1-4 percentage point yield difference that compounds.

How the four major US brokers handle it

Vanguard — uses VMFXX (Vanguard Federal Money Market Fund) as the default settlement fund for the brokerage account. VMFXX is a Treasury-heavy 2a-7 MMF that has consistently paid one of the top 7-day yields among major MMFs (roughly tracking the Fed funds rate minus 0.10-0.20 percentage points). With the federal funds target range at 3.50–3.75% (July 2026), VMFXX’s 7-day yield typically sits around 3.5-3.7%. No bank sweep is involved; the position is held as the fund balance, SIPC-protected. The 7-day yield is automatic — no action required by the account holder beyond keeping cash in the settlement position.

Fidelity — uses SPAXX (Fidelity Government Money Market Fund) as the default core position for new individual brokerage accounts as of 2024. SPAXX similarly pays near the Fed funds rate, typically tracking VMFXX within 0.10 percentage points. Fidelity also offers FDIC-Insured Deposit Sweep Program for IRA core positions and some retirement accounts (similar to Schwab’s structure, paying lower bank rates). For non-retirement brokerage accounts, the default is the MMF — competitive yields are automatic. For older Fidelity accounts (pre-2024), the default may be a lower-yielding cash position; check and convert to SPAXX manually if so.

Schwab — uses Schwab Bank Sweep as the default for all brokerage account types, including IRAs. The sweep moves cash to affiliated banks (currently Charles Schwab Bank and TD Bank Sweep partner) and pays bank-deposit rates set by Schwab Bank. As of 2026, the standard Schwab Bank Sweep pays a token rate — third-party trackers showed 0.01% in August 2026, and Schwab’s sheet has sat between 0.05% and 0.45% in recent years — meaningfully below the Fed funds rate. (The 3.2%–3.3% sweep rate Schwab publishes for its Intelligent Portfolios program is a different product.) Schwab offers manual movement of cash into Schwab money market funds like SWVXX (Schwab Value Advantage MMF) or SNVXX (Schwab Government MMF) that pay competitive yields near the policy rate (roughly 3.5-3.7%), but the move requires the account holder to actively choose. The default is the lower-yielding bank sweep, which is by design — the spread between what Schwab Bank pays customers and what it earns lending those deposits is a substantial revenue source for the brokerage.

Robinhood — uses Robinhood’s Cash Sweep Program, an FDIC-insured bank sweep across partner banks. The advertised APY varies by program tier (Robinhood Gold members get higher rates than free-tier). As of mid-2026, Gold members earn a swept-cash rate that tracks the federal funds rate (on the order of 3.5%); free-tier earns roughly 1%. The structure is similar to Schwab Bank Sweep but with more aggressive default rates because Robinhood’s revenue model relies less on the deposit spread.

The math of the default cost

The 7-day yield gap between MMF sweeps and bank sweeps at the same broker can be substantial. Approximate 2026 numbers (verify at broker’s current rate page):

Broker	Default sweep	Default APY	Best MMF available	Best MMF APY	Spread
Vanguard	VMFXX	~3.6%	VMFXX	~3.6%	0%
Fidelity (new account)	SPAXX	~3.5%	SPAXX or FZDXX	~3.5-3.6%	~0%
Schwab	Bank Sweep	~0.01–0.45%	SWVXX	~3.6%	~3.2–3.6%
Robinhood (Gold)	Cash Sweep	~3.5%	N/A	N/A	0%
Robinhood (free)	Cash Sweep	~1%	N/A	N/A	~2.5% vs Gold

For a typical brokerage account holding $50,000 in cash that the household considers liquid (emergency fund, planned but unscheduled spending, between-trade money), the annual cost of being in the wrong sweep is:

• $50,000 at 0.45% APY (the most generous recent Bank Sweep rate) = $225/year
• $50,000 at 3.6% APY = $1,800/year
• Spread: $1,575/year

For $200,000 cash (e.g., maturing CD or large bonus pre-investment), the annual spread is $6,300/year. Over 10 years of accepting the wrong default, the compounded forgone return is ~$75,000 at the $200K balance and ~$19,000 at the $50K balance.

How to fix it without changing brokers

If your broker is Vanguard or Fidelity (new account post-2024), the default is already the high-yield MMF and no action is required. Verify by checking your account “core position” or “settlement fund” balance — it should show as VMFXX (Vanguard) or SPAXX (Fidelity).

If your broker is Schwab, the action is to manually move cash from the Schwab Bank Sweep to a Schwab money market fund:

1. Log into the Schwab brokerage account online.
2. Identify the sweep balance (shown as “Cash & Sweep” or similar in the account summary).
3. Place a manual buy order for shares of SWVXX (Schwab Value Advantage MMF, requires $1 minimum, retail-class) or SNVXX (Schwab Government MMF, no minimum, often slightly lower yield but stricter Treasury composition).
4. The buy executes same-day at the fund’s NAV (typically $1.00 stable for MMFs). The cash moves out of the bank sweep into the MMF position.
5. When you need the cash for a trade or withdrawal, place a sell order; the proceeds settle into the bank sweep same-day for trades within the brokerage, T+1 for external transfers.

The friction is mild — one extra step per cash movement. The recovery is the 3-plus percentage point yield differential, immediately and continuously.

For Fidelity older accounts, the equivalent action is to move from FCASH (the older default) to SPAXX via a similar manual conversion.

State-tax considerations for MMFs

The yield comparison above is pre-tax. For state-tax-paying residents, the after-tax comparison depends on the MMF’s holdings:

• Treasury MMFs (e.g., Vanguard VMFXX, Schwab SNVXX, Fidelity FZDXX) — hold mostly US Treasury securities. Income from Treasuries is exempt from state income tax. For a California resident at the 9.3% state bracket, a 3.6% Treasury MMF yield is roughly equivalent (after state tax) to a 3.97% non-Treasury MMF yield. The exemption is meaningful for residents of high-tax states.

• Prime / corporate MMFs (e.g., Vanguard VMRXX with corporate paper exposure) — hold a mix of Treasury, agency debt, and short-term corporate paper. Income is fully taxable at both federal and state levels. For no-state-tax residents (TX, FL, NV, WA, etc.), prime MMFs can have slightly higher pre-tax yield than Treasury MMFs and the state-tax exemption is irrelevant — prime is usually the higher after-tax choice.

The right MMF choice depends on state of residence. A Texas resident might prefer a slightly higher-yielding prime MMF; a California resident almost certainly prefers a Treasury MMF for the state-tax exemption — the same asymmetry that drives the after-tax math of T-bills versus high-yield savings versus money market funds.

The break-the-buck risk

Money market funds maintain a $1.00 net asset value (NAV) by holding only very-short-duration assets and following SEC Rule 2a-7 portfolio constraints. The “break the buck” scenario — NAV falling below $1.00 — has happened twice in modern US MMF history:

• 1994 — Community Bankers US Government Fund broke the buck due to derivative losses, NAV fell to $0.96. Fund was liquidated, investors recovered most principal but lost a small portion.
• 2008 — Reserve Primary Fund broke the buck due to Lehman Brothers commercial paper exposure, NAV fell to $0.97. The event triggered a broader run on prime MMFs that was eventually backstopped by Treasury guarantees during the crisis.

Since 2010, the SEC has tightened MMF rules under Rule 2a-7 amendments and 2014/2016 reforms. Treasury MMFs are required to hold only government-backed securities; prime MMFs must implement liquidity fees and gates during stress periods. The break-the-buck risk for Treasury MMFs is essentially zero in non-crisis conditions. The risk for prime MMFs is small but non-zero in extreme stress scenarios.

For typical brokerage cash management, the historical track record favors Treasury MMFs as the lowest-risk MMF choice, with prime MMFs as a slightly higher-yield-with-slightly-higher-tail-risk alternative. Both vastly outperform a 0.45% bank sweep on yield over multi-year horizons — and for cash that can sit locked for four to fifty-two weeks, buying Treasury bills directly through TreasuryDirect extends the same state-tax-exempt logic one step further.

SIPC and FDIC coverage interaction

For Vanguard and Fidelity (MMF-default brokerages), idle cash held in the MMF settlement position counts toward the broker’s SIPC $500K securities limit. Most retail investors have far less than $500K in any single brokerage account, so the limit rarely binds. For households with very large brokerage balances ($500K+), splitting across two brokers provides cleaner coverage than concentrating.

For Schwab and Robinhood (bank-sweep brokerages), idle cash held in the bank sweep counts toward FDIC at each partner bank. Schwab Bank Sweep uses Charles Schwab Bank as the primary partner with $250K coverage; if cash exceeds that, it overflows to the affiliated partner bank for additional $250K. Fidelity Cash Management Account uses 5 program banks for up to $1.25M aggregated FDIC coverage. For households with very large cash balances, the bank sweep multi-bank structure can actually provide higher aggregate insurance than a single MMF position (which is capped at SIPC $500K total).

When to consider moving brokers entirely

If you are at Schwab and the manual MMF conversion is friction you do not want to do regularly, switching to a brokerage where the default is the higher-yield MMF (Vanguard or Fidelity) eliminates the friction permanently. Brokerage ACATS transfer is free, takes 5-7 business days, and is reversible. The transfer preserves cost basis, all positions, and tax-lot history. The transition cost is minimal; the yield recovery is permanent.

If you are at Robinhood free-tier and the upgrade to Gold ($5/month or $50/year) gets you the higher-yield sweep, the math typically favors Gold for any cash balance above $2,000 (where the ~2.5-point yield differential exceeds the Gold fee).

If you are already at Vanguard or Fidelity with the high-yield default, the switching analysis above does not apply — you are already capturing the benefit.

What this guide does not cover

This guide focused on the four major US brokers’ cash sweep mechanics. It does not cover:

• Specific MMF expense ratio comparison — VMFXX, SPAXX, SWVXX all have slightly different expense ratios that affect net yield by 0.05-0.20 percentage points. The differences are real but small relative to the 3-point bank-sweep gap.
• Treasury Direct vs broker-bought T-bills — for cash you can lock up for 4-52 weeks, buying T-bills directly via TreasuryDirect.gov can sometimes yield more than MMFs and provides identical state-tax exemption. Worth its own analysis.
• Cash management accounts (Wealthfront Cash, Betterment Cash Reserve, SoFi Money) — different product category, sometimes with higher yields, different coverage structure. Out of scope.
• International brokers — non-US brokerages have their own structures.

For the mainline US brokerage cash management case, the comparison above is complete.

What to verify before moving cash

Always check the broker’s current published rates before executing the optimization:

• Vanguard MMF yields: investor.vanguard.com/investment-products/mutual-funds/money-market
• Fidelity MMF yields: fidelity.com/mutual-funds/category/money-market-funds
• Schwab MMF yields and Bank Sweep APY: schwab.com/cash-investments
• Robinhood Cash Sweep APY: robinhood.com/cash-management

The structural mechanics in this guide are stable. What changes weekly is the 7-day yield of each MMF (tracks Fed funds) and the published Schwab Bank Sweep rate. Pull current numbers before the conversion — if the spread has narrowed to under 1 percentage point, the optimization is less consequential; if it remains above 3 percentage points, the optimization is essentially free money.

Sources

• Money market fund regulatory framework, the seven-day yield definition, and the SEC reforms that govern net asset value stability: SEC — Money Market Funds.
• Securities Investor Protection Corporation (SIPC) protection scope — what it covers in a brokerage failure and what it does not: SIPC — What SIPC Protects.
• FDIC pass-through deposit insurance mechanics for bank sweep programs: FDIC — Deposit Insurance.
• Federal funds rate target, the upstream determinant of all sweep yields: Federal Reserve — Open Market Operations.
• Vanguard Federal Money Market Fund (VMFXX) prospectus and yield history: Vanguard — VMFXX.