Bank Sweep vs. Money Market Sweep: What's the Difference?
Two brokerage accounts can both describe their default cash option as a “sweep” and still be doing something structurally different with the money underneath.
The short answer
A bank sweep moves uninvested cash into deposit accounts held at one or more partner banks, similar in structure to a savings account. A money market sweep instead invests that cash in shares of a money market fund, which holds short-term debt instruments rather than sitting as a bank deposit. Both exist to give idle cash somewhere to earn a return, but the underlying vehicle, the yield mechanics, and the type of protection involved can differ meaningfully.
How a bank sweep works
With a bank sweep, uninvested cash in a brokerage account is moved, usually automatically, into deposit accounts at one or several partner banks behind the scenes. From the account holder’s perspective, the cash still appears as a single balance and functions the same as any other brokerage cash — available to fund trades or be withdrawn. The bank deposit structure is what determines how the cash is protected and where its yield comes from.
How a money market sweep works
A money market sweep instead purchases shares of a money market fund with the uninvested cash. These funds hold a portfolio of short-term, relatively stable debt instruments and aim to maintain a steady share price, distributing earnings as yield. Unlike a bank deposit, a money market fund is an investment product, which changes how it’s structured and protected, even though day to day it can feel just as liquid and accessible as cash.
Differences worth understanding
- Yield mechanics. Bank sweep yield generally tracks the rates the partner banks are willing to pay on deposits, while money market sweep yield tracks the return generated by the fund’s underlying holdings, and the two can diverge depending on conditions.
- Type of protection. Deposits at a bank are protected differently than shares in an investment fund, which is a key reason the choice between the two sweep types matters beyond just the yield number.
- Structure, not just label. Because both options are commonly called a “sweep,” the underlying mechanics aren’t always obvious from the name alone, and two brokerages using the same term can mean different things.
Why brokerages offer both — or just one
Some brokerages default every account into a single sweep type, while others let account holders choose between a bank sweep and a money market option, sometimes with different yields attached to each. The choice a firm makes often reflects its own business model as much as anything else, since bank sweep arrangements can generate revenue for the brokerage in ways a money market sweep may not. Understanding how sweep cash differs from money tied to a pending settlement is a useful complement to understanding the sweep vehicle itself, since both affect what a “cash balance” actually represents.
What to weigh
The practical difference between a bank sweep and a money market sweep often comes down to yield and the specific protection that applies to the cash, both of which can be checked directly rather than assumed. Because the word “sweep” alone doesn’t specify which structure is in use, looking at how a given account’s default cash option is actually built tends to be more informative than the label on the statement.