Cash Account vs Margin Account: The Rules Side by Side
A cash account trades only with money already paid in, while a margin account lets the broker lend against your holdings. The cash account's limit is settlement timing under Regulation T; the margin account's limit is a loan with a 25% maintenance floor, and it can lose more than you deposit.
Most brokerage applications ask this question on the first screen and many pre-select margin. The choice decides two things: whether you can ever owe the broker money, and which rule limits how often you can trade.
What each one is
A cash account buys only with money that is paid in. Under Regulation T, the Federal Reserve rule for broker credit (12 CFR 220.8), a broker may buy for you in a cash account if there are sufficient funds, or if it accepts in good faith that you will pay in full before selling. Nothing is borrowed.
A margin account attaches a loan to the brokerage account. The broker lends against your holdings, so you can buy more than your cash covers and sell short. The mechanics of the loan are on the margin account page; this page is about how the two account types differ.
Where they differ
How much you can lose. In a cash account the worst case is that what you bought becomes worthless. In a margin account the debt stays fixed while the collateral falls, so a large enough drop can leave you owing the broker after everything is sold.
When you must pay. A cash-account purchase must be paid within one “payment period”, which Regulation T (12 CFR 220.2) defines as the standard settlement cycle plus two business days. SEC Rule 15c6-1 sets that cycle at one business day, T+1, so the payment period is three business days. In a margin account the loan covers the purchase instead.
When sale proceeds can be reused. In a cash account the proceeds of a sale settle on the next business day. You may buy with them straight away, but selling that new position before the proceeds settle is what brokers call a good faith violation. In a margin account the broker’s loan bridges the gap, so this timing problem mostly disappears.
What happens after a violation. Selling a cash-account purchase before paying for it is freeriding, and Regulation T 220.8(c) then withdraws the right to delay payment for 90 calendar days: purchases need cash in the account first. Good faith violations are handled by broker policy; Fidelity, for example, restricts a cash account for 90 days after three in 12 months.
What the regulators require of a margin account. Regulation T sets the initial requirement at 50% of the purchase (12 CFR 220.12), so $10,000 of your money buys up to $20,000 of stock. FINRA Rule 4210 sets the maintenance floor at 25% of market value and requires equity of at least $2,000, and brokers may set their own requirements higher.
Day trading. A cash account was never subject to the pattern day trader rule. On the margin side, FINRA replaced the pattern day trader designation, its day-trade count and its $25,000 minimum with intraday margin standards effective 4 June 2026 (Regulatory Notice 26-10). Firms may phase the change in until 20 October 2027, so some brokers may still apply the old rules.
Where they agree
Both pay the same spread and commission on every round trip. The account type changes the financing, not the cost of trading.
Both settle on the same T+1 cycle. Settlement happens either way; a margin account simply lends across it, as the settlement page explains.
And neither changes the price path. A stock moves the same whether it was bought with cash or with a loan. Only the size of the result changes.
A worked example
Take a hypothetical $10,000 and a stock at $50. In cash, that buys 200 shares. On margin at Regulation T’s 50%, it buys 400 shares worth $20,000, with $10,000 borrowed.
The stock falls 20% to $40. The cash position is worth $8,000: a loss of $2,000, or 20%. The margin position is worth $16,000 against the same $10,000 debt, leaving $6,000 of equity: a loss of $4,000, or 40%. Equity is 37.5% of the position, above FINRA’s 25% floor, so no maintenance call yet.
The stock rises 20% to $60 instead. The cash account shows a gain of $2,000. The margin account shows a gain of $4,000 before interest, because the 400 shares are worth $24,000 against the $10,000 loan. The same 20% move doubled both outcomes, and the interest is charged either way.
Which one to use
Open a cash account when you are buying to hold, or learning. Its worst case is capped at the deposit, and settlement timing is the only rule that limits you.
Choose margin when you need to sell short, because a short sale borrows shares and cannot be done in a cash account. Short selling covers what that loan involves.
Choose margin when frequent trading keeps colliding with settlement, and you would rather pay interest on occasional borrowing than wait a business day for proceeds.
Stay in cash when the only reason for margin is buying more. The worked example shows the price: the same 20% fall costs 40% of the equity at 2:1 instead of 20%.
The original data
The pattern day trader rule is where cash and margin used to part ways most visibly, and the videos show the change. Of 12 titles in the 24,971-video search study that name the PDT rule, 7 are about its 2026 end, with 342,155 views between them.
Margin itself appears in 33 titles from 30 channels, at a median of 30,392 views. And 46 titles are pitched at small accounts, at a median of 44,824.5 views: the accounts for which the cash-or-margin choice, and the old $25,000 line, mattered most.
What it means: much of the older advice on choosing between cash and margin was built around a rule that ended on 4 June 2026. The rules that remain are settlement on the cash side and the 50%, 25% and $2,000 figures on the margin side.
When it fails
A cash account fails through settlement mistakes, not losses. A trader sells a winner on Monday, buys something else with the proceeds the same afternoon, and sells that too before Tuesday. Nothing lost money, but the account now carries a violation, and at many brokers three in 12 months means 90 days of trading only with cash that settled beforehand.
A margin account fails through the loan’s schedule. The maintenance calculation runs on the broker’s clock, and a fall to the line brings a call whether or not the idea later proves right. A broker may sell positions without contacting you, so being right three weeks later does not undo the sale.
Both fail when the account type is chosen by default. Margin pre-selected on an application is still margin, with its interest and its larger downside, even if the loan is never used on purpose.
And moving to margin to escape settlement fails when the real problem is frequency. If a cash account keeps producing violations, the trades are coming faster than the money can recycle, and a loan makes that pace possible without making it wise.
Related
The margin account page works through the maintenance arithmetic and when the call arrives. Settlement explains the T+1 cycle that governs every cash-account trade. And the pattern day trader page covers the rule that ended in June 2026 and what replaced it.
Start in cash and let a specific need move you to margin, not the default checkbox on the application. If you cannot name the trade that needs the loan, the loan is only adding a way to lose more than the deposit.
— Michael Whitman
This page is educational, not financial advice. Test every idea on your own charts before risking money.