Brokerage Cash Sweep Accounts Explained: What Your Uninvested Cash Really Earns

When you sell a stock, deposit money into a brokerage account, or receive a dividend, that cash has to sit somewhere until you invest it. At most brokerages, it lands automatically in a cash sweep, sometimes called a core position or settlement account. Many investors never look closely at where that money goes or what it earns. That can be an expensive blind spot. Depending on the brokerage and the program, uninvested cash might earn a competitive yield, or it might earn very little while the firm keeps most of the interest. This guide explains how cash sweeps work, how they are protected, and how to make sure idle cash in your brokerage account is working for you.

This article is general education, not personalized investment advice. Sweep programs, rates, and options vary by firm and account type and can change at any time, so review your own account documents and current disclosures.

What a cash sweep is

A cash sweep is an automatic arrangement that moves uninvested cash in a brokerage account into a designated holding vehicle. Instead of leaving cash idle, the brokerage sweeps it into a bank deposit program, a money market fund, or another option, depending on the firm and the account. When you buy a security, money is pulled back out of the sweep to pay for it. When you sell, the proceeds flow back into the sweep once the trade settles.

The convenience is real. You do not have to move money manually to keep it accessible for trades, and your cash usually earns something rather than nothing. The catch is that the sweep is chosen for you by default, and brokerages make decisions about which vehicle to use, how much interest to pass through, and which banks hold your money. Those decisions can benefit the firm more than the customer, so understanding the default is the first step toward improving it.

Bank deposit sweep programs

The most common sweep type at many brokerages is a bank deposit sweep. Your cash is deposited into one or more partner banks, often called program banks. Once the money is at an FDIC-insured bank, it is eligible for deposit insurance, up to $250,000 per depositor, per insured bank, for each ownership category. Many programs spread cash across multiple program banks, which can extend total FDIC coverage well beyond $250,000 for a single account.

Bank sweeps can be very safe for principal, but they are often where the yield gap appears. The brokerage, or an affiliated bank, typically earns interest on the deposited cash and decides how much to pass along to you. In many cases, especially for smaller balances, the rate paid to customers has been far below what a money market fund or high-yield savings account pays. Some firms offer tiered rates, paying more for larger balances or for customers with advisory relationships. The difference between what the bank earns and what you receive is a source of revenue for the firm. Cash sweep practices at several large firms have drawn regulatory scrutiny and lawsuits in recent years, and some firms have raised their sweep rates in response.

Money market fund sweeps

Some brokerages sweep cash into a money market fund instead of, or in addition to, a bank deposit program. A money market fund is a mutual fund that invests in short-term, high-quality debt, such as Treasury bills, government agency securities, and repurchase agreements. These funds aim to keep a stable share price of $1 and pay a yield that tends to move with short-term interest rates.

Money market fund yields often track market rates more closely than many bank sweeps, though they charge expense ratios that reduce returns. The key difference in protection is that money market funds are not FDIC insured. They are securities, and while they are designed to be very low risk and government money market funds hold mostly government-backed assets, it is possible for a fund to lose value, though this has been rare historically. If your brokerage defaults to a money market fund sweep, you may already be earning a market-based yield. If it defaults to a bank program, a money market fund may be available as a separate investment you can buy.

How SIPC protection fits in

The Securities Investor Protection Corporation, or SIPC, protects customers if a brokerage firm fails and customer assets are missing. SIPC coverage is up to $500,000 per customer, including up to $250,000 for cash held at the brokerage. It covers securities such as stocks, bonds, and money market fund shares, as well as cash that the brokerage holds directly as a free credit balance.

SIPC does not protect against investment losses, such as a drop in a stock price or a decline in a fund's value. It is designed to restore your property if the firm itself fails or misappropriates assets. Cash in a bank deposit sweep is generally not covered by SIPC once it is deposited at program banks, because it is protected by FDIC insurance instead. Understanding which protection applies to each piece of your cash helps you see where any gaps might be, especially if you hold large balances.

Checking FDIC coverage across program banks

If your brokerage uses a bank deposit sweep, it is worth reviewing the list of program banks. Deposit insurance limits apply per bank, so if you already have money at one of those banks through a personal checking or savings account, your sweep cash and your other deposits at that bank are combined for insurance purposes. In some cases, that could push your total at one bank over the $250,000 limit for a given ownership category.

Many brokerages let you view the program bank list and, in some cases, exclude specific banks from receiving your sweep cash. Your account disclosures should explain the order in which banks receive deposits and the maximum coverage available through the program. Also note that sweep coverage depends on accurate recordkeeping by the brokerage so that deposits can be attributed to you as the owner. For most investors with modest cash balances, this is not a major concern, but if you hold large amounts in cash, reviewing the program details is a prudent step.

How much the yield gap can cost

The cost of a low sweep rate can be surprisingly large over time, especially if you hold cash for months or years. Consider an illustrative example. Suppose you have $30,000 sitting in a brokerage account. If the sweep pays an example rate of 0.5 percent, you would earn about $150 in a year. If you moved that cash into an option paying an example rate of 4.5 percent, you would earn about $1,350. The difference, around $1,200 per year, could cover fees, contributions, or simply compound in your favor.

These numbers are hypothetical, and actual rates vary widely over time. When short-term rates are near zero, the gap between options shrinks. When rates are higher, the gap can widen. The key idea holds in most environments: cash sitting in a low-yield sweep is often earning less than it could, and the difference can be meaningful for larger balances or longer holding periods.

Retirement accounts and robo-advisors

Cash sweeps exist in IRAs, 401(k) brokerage windows, and other retirement accounts too, not just taxable accounts. Cash in an IRA can sit for long stretches after a rollover, a contribution, or a sale, and if the sweep rate is low, that idle money may be quietly underperforming. A common mistake is rolling a 401(k) into an IRA and forgetting to invest the proceeds, leaving the full balance in the sweep for months.

Robo-advisors and managed accounts often include a cash allocation as part of their portfolios. In some cases, that cash is held in a bank sweep program that benefits the provider. Review how much of your managed portfolio is held in cash, what that cash earns, and whether you can adjust it. Some providers explain their cash allocation clearly in their disclosures, while others require a closer read to understand the tradeoffs.

Options for idle cash at a brokerage

If your sweep pays a low rate, you usually have alternatives within the same brokerage. One option is to buy a money market fund directly. Many brokerages offer government, Treasury, and prime money market funds that you can purchase like any other fund. Some firms let you choose a money market fund as your core position, so cash automatically goes there instead of a low-yield bank program.

Another option is Treasury bills, which you can often buy through a brokerage at auction or on the secondary market. T-bills are backed by the U.S. government and are exempt from state and local income taxes. Short-term Treasury ETFs offer similar exposure with daily liquidity. Finally, you can move cash out of the brokerage entirely into a high-yield savings account at a bank, especially for emergency savings you want separate from your investments. Each option has tradeoffs in liquidity, protection, and convenience, so match your choice to how soon you might need the money.

Keeping some cash in the sweep

Moving all of your cash out of the sweep is not always necessary or practical. Most trades now settle one business day after the trade date, and you need cash available to pay for purchases. Keeping a modest buffer in the sweep can help you avoid trade settlement problems, especially in accounts where you buy and sell frequently.

Some brokerages automatically sell shares of a money market fund to cover purchases, but others require you to place a sell order first. Know your brokerage's process so you do not accidentally trigger a good faith violation or a margin loan. A sensible approach is to leave a small amount in the sweep for routine activity and move larger or longer-term cash into a higher-yielding option.

Taxes on sweep and money market income

Interest earned in a bank sweep is generally taxed as ordinary interest income at the federal and state levels in taxable accounts. Money market fund distributions are typically taxed as ordinary dividends and do not qualify for the lower qualified dividend rates. Treasury money market funds and T-bills may offer state tax benefits, because interest from U.S. Treasury securities is exempt from state and local income taxes, though the treatment of fund distributions depends on the fund's holdings and your state's rules.

In retirement accounts, these tax distinctions generally do not apply while the money stays in the account, so the main focus is maximizing yield and making sure cash is invested according to your plan. For taxable accounts, compare after-tax yields when choosing between options, especially if you live in a high-tax state.

The bottom line

Brokerage cash sweeps are convenient, but the default option is not always in your best interest. Bank deposit sweeps can offer strong FDIC protection across multiple program banks, but they often pay far less than money market funds or high-yield savings accounts. Money market fund sweeps tend to track market rates more closely but are not FDIC insured. Check what your sweep pays, review program bank coverage if you hold large balances, and move longer-term cash into a higher-yielding option while keeping a modest buffer for trades. A few minutes reviewing your account can turn idle cash into money that is actually working for you.