Cash management accounts vs. banks: how sweep programs really work

A cash management account looks like a checking account — routing number, debit card, bill pay, direct deposit — but lives at a brokerage rather than a bank. Fidelity, Schwab, Vanguard, and a wave of fintechs all offer one, typically advertising yields far above the big banks and FDIC coverage of $1-5 million, several times the normal $250,000 limit. Both claims are usually true, and both depend on machinery most account holders have never examined: the sweep program. Understanding that machinery is the difference between a genuinely better checking account and a structure you're trusting blindly.

The sweep: your money doesn't live where you think

A brokerage isn't a bank and can't hold your deposits itself. Instead, each night it 'sweeps' your cash to one of two destinations: a money market mutual fund, or a rotating list of partner banks ('program banks'). In a bank sweep, your $400,000 might sit as $200,000 at Bank A and $200,000 at Bank B — real deposits, at real banks, titled for your benefit. Because FDIC insurance applies per depositor PER BANK, spreading cash across multiple program banks multiplies coverage: five banks × $250,000 = $1.25 million of pass-through insurance on a single account. That's the whole trick behind the big coverage numbers — perfectly legitimate, and dependent on accurate record-keeping connecting you to those deposits.

FDIC vs. SIPC: different promises

The two protections get conflated constantly. FDIC insures bank deposits against bank failure, up to $250,000 per depositor, per bank, per ownership category — it guarantees you get your dollars back. SIPC protects brokerage customers against the BROKERAGE failing and customer assets going missing — up to $500,000 including $250,000 for cash — but it never protects against investments losing value. A money market fund in your CMA is covered by SIPC custody protection, not FDIC; its $1.00 share price is extremely stable (government MMFs have essentially never 'broken the buck') but is a fund price, not a guarantee. Bank-swept cash is FDIC territory; fund-swept cash is SIPC territory. Both have strong track records; they are simply different legal animals.

The fine print that matters

• Program bank lists change: brokerages add and drop partner banks; if you independently bank with a program bank, your combined deposits there share one $250,000 limit — check the list if you hold large balances.
• Coverage caps are per-program: '$5 million FDIC' assumes enough program banks have capacity; excess cash above the program's ceiling may sit uninsured or in an MMF.
• The brokerage keeps the spread on bank sweeps: program banks may pay 4%+ for the deposits while your sweep credits 0.4% — the difference is a major revenue line. Opting into the MMF sweep (where offered) captures most of it back.
• Transfers out of sweeps take a day: same-day large wires can require the sweep to unwind first; test the timing before you need it for a house closing.
• Regulation D-style transfer limits generally don't apply, but some CMAs impose their own outbound limits — read the schedule.

Who should switch, and who shouldn't

A CMA shines as the hub for people who already invest at the brokerage (instant transfers to buy funds), hold meaningful cash buffers ($10,000+ where yield matters), travel (many reimburse all ATM fees worldwide), or want simplicity — one login for cash and investments. Traditional banks still win for people who deposit cash regularly (CMAs handle physical cash poorly or not at all), need same-day cashier's checks and notaries, want in-person problem resolution, or need certain instant payment rails — Zelle support at CMAs remains spotty. Many households land on a hybrid: a small local checking account for cash, checks, and branch services, with the CMA holding the buffer and paying the bills.

1. List your last three months of banking actions: cash deposits, ATM use, checks written, wires, Zelle.
2. Check which a CMA handles: if cash deposits appear, keep a bank account in the stack.
3. Compare your current blended yield on all cash against the CMA's sweep options.
4. If switching, migrate direct deposit and autopays in one billing cycle, keeping the old account open a month as a catch net.

The bottom line

Cash management accounts deliver on their headline promises through real, inspectable machinery: nightly sweeps to program banks for multiplied FDIC coverage, or to money market funds for near-market yield under SIPC custody. The structure is sound at major brokerages, weaker at ledger-dependent fintechs, and always worth one hour of reading: know where the sweep goes, who insures what, and which default setting is quietly costing you yield. For most households with real cash buffers, that hour is worth four figures a year.