Brokerage Sweep Programs Pay Your Cash a Yield the Prospectus Chooses
Cash sitting in a brokerage account earns whatever the sweep program pays, and that number is written into a contract rather than set by the market. The gap between sweep yield and short-term Treasury yields has run into whole percentage points. What follows is how the arrangement works, where the money goes, and what a saver can do about it.
The 0.01% Yield Problem
A sweep program moves uninvested cash out of your account each night and into a destination the broker chooses. That destination might be a bank deposit or a money market fund. The rate you receive is not the federal funds rate, not the yield on a three-month Treasury bill, and not anything you negotiated. It is a figure the broker sets.
In low-rate years, sweep yields on some accounts have printed at a fraction of a percent. A widely repeated piece of advice says to keep an emergency fund in your brokerage account for easy access. That advice treats the account as a container. It ignores the fact that the container pays its own rate, chosen by the firm holding your money.
When you leave cash in a sweep, you are effectively lending to the broker or its partner bank. The broker decides the interest on that loan. The comparison that matters is not the return on your invested positions. It is what the same dollar would earn in a Treasury bill or a money market fund you selected yourself.
How Sweep Programs Actually Work
Two structures dominate. In a bank sweep, the broker deposits your cash into one or more affiliated banks, and those deposits fund the bank's lending and investment activity. In a money market sweep, the cash buys shares of a money market fund, often one managed by an affiliate of the broker.
Both structures put your cash to work for an institution. The difference is who keeps the spread. With a bank sweep, the bank pays you a deposit rate and earns a higher rate on the assets it holds. With a fund sweep, the fund charges an expense ratio, and the broker may receive fees for directing cash into it.
The yield is set by contract, not by competition. A competitive market would push the rate toward what short-term cash actually earns. A sweep program does not have to. The terms live in the account agreement and the fund prospectus, documents most account holders accept without reading.
Consider a concrete example. Suppose a broker's bank sweep pays 0.05% and the affiliated money market fund yields 4.5%. On a $20,000 cash balance, the sweep pays $10 a year. The fund would pay roughly $900. That $890 difference is the cost of the default. The broker keeps the spread, which on a large book of client cash can add up to substantial revenue. The exact figures vary by firm and by rate environment, but the pattern is consistent: the sweep rate lags the market rate by a wide margin, and the broker captures the difference.
The Prospectus Is the Contract
The sweep terms are buried in the account agreement, sometimes in a schedule of fees and sometimes in a separate disclosure booklet. The language typically gives the broker discretion to change the yield at any time, often without advance notice to you. That single clause explains why sweep rates can sit still while market rates move.
A money market fund's yield moves with its holdings. A sweep rate does not have to. The fund may hold Treasury bills and commercial paper that reprice constantly, while the sweep rate you receive is a policy decision. The prospectus says as much, in language written to satisfy disclosure rules rather than to inform a saver.
The practical comparison is direct. Look up the current yield on a three-month Treasury bill, then look up what your sweep pays. If the gap is wide, the contract is doing the work. This is the same pattern this site has described in BNPL contracts and late fee schedules, where the headline term is not where the money is made.
What You Give Up in Yield
The gap between sweep yields and short-term Treasury yields has at times run into the low single digits in percentage terms, depending on the account and the rate environment. On a $50,000 cash balance, a two-point gap is $1,000 a year. A four-point gap is $2,000. Those figures are illustrative, not a quote from any specific firm.
The broker earns the spread. In a bank sweep, the affiliate bank pays a deposit rate and earns a higher return on the assets it funds. In a fund sweep, the broker may collect distribution or service fees. Neither arrangement is illegal, and both are disclosed. The disclosure is legal, not clear.
Money market funds are not insured against loss, though actual losses have been rare in practice. Treasury bills carry the full faith and credit of the issuing government. A bank sweep deposit may be eligible for deposit insurance up to a limit, which is a real advantage for very large balances. That insurance is the trade-off worth naming.
Why the Advice Persists
Brokers promote the sweep as convenience. Cash is available immediately for trades, transfers, and withdrawals, and the account holder never has to make a decision. The convenience is real. The cost is the yield you do not receive, and it is invisible unless you look for it.
Advisors do not always surface the alternative. A representative may not mention that the same cash could sit in a money market fund with a higher yield, or that Treasury bills can be bought directly in many accounts. The omission is not necessarily deliberate. The sweep is the default, and defaults are sticky.
Investor inertia does the rest. Moving cash requires a decision, a trade, and sometimes a phone call. The account agreement is written to make the default easy and the alternative slightly less so. This site has made a similar argument about student loan deferment and capitalization, where the quiet default is the expensive one.
What to Do Instead
Ask your broker for the current sweep yield in writing, along with the yield on the money market fund available in the same account. Put the two numbers side by side. The request is simple, and the answer is often enough to prompt a change.
Move idle cash into a money market fund you select, or buy Treasury bills directly if your account supports it. Many brokers offer both, and the trade is a few clicks. If your cash is a true emergency reserve, compare a high-yield savings account as well, since deposit insurance may matter more than a few basis points.
Read the sweep disclosure once a year. Rates change, and so do the terms. If the account agreement gives the broker discretion to change the yield without notice, that clause is the one to remember. A related piece on permanent life insurance and compound interest makes the same point about contracts that quietly redirect value.
Questions to Ask Before You Move Cash
Before shifting a large cash balance, a few questions clarify the trade-offs. First, what is the current sweep yield, and how often does it change? Second, what money market funds are available in the same account, and what are their expense ratios? Third, are there any fees for moving cash between the sweep and a fund, or for buying Treasury bills? Fourth, what is the settlement time for each option, and does it matter for your spending needs? Fifth, if you hold a very large balance, does deposit insurance apply, and up to what limit? The answers will differ by firm, but asking them puts the decision on your terms.
One more consideration: taxes. Interest from Treasury bills is exempt from state and local income tax, while money market fund distributions may be fully taxable. That difference can narrow or widen the yield gap depending on your tax bracket. A high-yield savings account pays interest that is fully taxable. None of this is advice, but it is the kind of detail that rarely appears in a sweep disclosure.
This article is informational and does not constitute personalised investment, tax, or legal advice. Consider your own circumstances or consult a qualified professional before changing how your cash is held.
