Cash vs Margin Accounts: Mechanics, Risks and How to Choose

Direct answer: A cash account requires you to pay for securities in full using the settled cash already in the account. A margin account lets you borrow up to 50% of the purchase price from your broker, magnifying both gains and losses. The Federal Reserve's Regulation T sets that initial 50% minimum; your broker can require more. Margin amplifies returns in good markets and amplifies losses in bad ones, and a margin call (a broker demand that you deposit more funds or securities) can force you to sell at the worst time. Most investors are better served by a cash account unless they have a specific, deliberate use case for leverage.

What Is a Cash Account?

A cash account is the default brokerage account type. Every security purchase must be paid for in full using settled cash that is already in the account before the trade is placed. There is no borrowing from the broker, no interest charges, and no risk of a margin call.

Under the current T+1 settlement cycle (adopted in the United States in May 2024), most equity trades settle one business day after the trade date. That means cash from a stock sale is not available to reuse until the following business day. Placing a new trade before the proceeds from a prior sale have settled creates what the SEC calls a good-faith violation if you then sell the new position before the original cash settles, or a freeriding violation if you buy a security with no settled cash at all and sell it before paying for it. Brokers track these violations and will restrict accounts with repeated occurrences, typically by requiring the cash to be on hand before any new purchase for a period of 90 days.

The settlement constraint is a minor inconvenience for long-term investors who are not recycling proceeds rapidly. For active traders who want to reuse the same capital across multiple trades in a single day, a cash account creates a genuine bottleneck, which is one legitimate reason to consider a margin account.

What Is a Margin Account?

A margin account allows your broker to lend you money against the securities held in the account, using those securities as collateral. The Federal Reserve's Regulation T governs the initial margin requirement: you must put up at least 50% of the purchase price of any security you buy on margin. The broker lends you the remaining 50%. If you buy $20,000 worth of stock on margin, you contribute at least $10,000 of your own funds and borrow the other $10,000 from the broker.

The broker charges margin interest on the borrowed amount, accrued daily and compounded. Rates vary by broker and by the size of the loan. A position held on margin for months or years accumulates interest that reduces the effective return. In a sideways market where the position generates no gain, margin interest represents a guaranteed loss.

FINRA Rule 4210 establishes the maintenance margin requirement: the minimum equity you must maintain as a percentage of the total market value of your positions. FINRA sets the regulatory floor at 25%, but most brokers require 30% to 40% for standard equity positions, and higher percentages for volatile or concentrated positions. If your account equity falls below the broker's maintenance margin, you receive a margin call.

One often-overlooked feature of margin accounts is hypothecation: by signing a margin agreement, you grant the broker the right to lend your securities to short sellers. Your shares may be lent out while you hold them, typically without your knowledge of which shares are involved on any given day. The broker keeps any fees from this securities lending arrangement; you keep dividends but may receive substitute payments for dividends while your shares are lent, which can have different tax treatment.

How a Margin Call Works: A Real Example

Consider an investor who buys $20,000 of stock using $10,000 of their own cash and $10,000 borrowed from the broker on margin. Their initial equity is $10,000, representing 50% of the position value.

The stock declines 40%. The position is now worth $12,000. The loan remains $10,000. The investor's equity is $12,000 minus $10,000, equal to $2,000, which is only 16.7% of the total position value. At a 30% maintenance margin requirement, the investor needs $3,600 in equity ($12,000 times 30%). They are $1,600 short.

The broker issues a margin call requiring the investor to deposit $1,600 in cash or sell enough securities to bring the equity back above the maintenance level. Most brokers give 24 to 48 hours to meet the call, though margin agreements typically give the broker the right to liquidate positions without notice at their discretion. In a fast-moving market, the broker may sell before you have time to respond.

This forced liquidation at the worst time is the central risk of margin investing. It turns paper losses into realized losses at precisely the moment when holding through the decline would have been the better outcome. The investor who bought $20,000 of stock without margin and watched it fall 40% still holds $12,000 and can wait for recovery. The investor who used margin may have been forced out of the position at $12,000 with a net loss larger than the market loss itself once the loan repayment is accounted for.

Pattern Day Trader Interaction

FINRA defines a pattern day trader as any customer who executes four or more day trades within five business days in a margin account, where those day trades represent more than 6% of total trading activity in the account over the same period. Once flagged as a pattern day trader, the account must maintain a minimum equity of $25,000 before any further day trading is permitted. Falling below $25,000 prevents you from day trading until the balance is restored.

The pattern day trader rule applies only to margin accounts. A cash account holder can make as many day trades as they want without triggering PDT status, because the PDT rule is a FINRA rule governing margin accounts specifically. The practical constraint in a cash account is T+1 settlement: you can only use settled cash, so you cannot effectively trade in and out of the same position multiple times in a single day with the same capital unless you have a cash balance large enough to fund each trade independently.

Investors under $25,000 who want to day trade face a genuine structural conflict: the margin account they need to avoid the settlement constraint is the same account type that subjects them to the PDT rule. The only compliant paths are to maintain $25,000 in the margin account, limit day trades to three or fewer per five business days, or use a cash account and accept the settlement constraint.

5 Failure Modes of Margin Accounts

1. Forced liquidation at the bottom. A margin call during a sharp decline forces selling at or near the lowest point. This converts a temporary mark-to-market loss into a permanent realized loss and removes the position precisely when recovery begins.
2. Margin interest erodes returns in sideways markets. Leverage amplifies gains only if the underlying position appreciates faster than the borrowing cost. In a flat market, margin interest is a guaranteed headwind.
3. Securities lending risk. Margin account holders implicitly grant consent for their shares to be lent. While uncommon, operational failures at the broker can create complications, and substitute dividend payments may be taxed differently than qualified dividends.
4. Double-leverage trap. Buying a 2x or 3x leveraged ETF on margin combines the daily reset decay of the ETF with broker-level leverage, creating compounded volatility that can devastate a position even when the underlying index has a modest positive return over the period.
5. Overconfidence amplification. Behavioral finance research consistently shows that leverage amplifies not just position sizes but investor confidence and loss-chasing behavior. A leveraged investor who is wrong is wrong with more money; a leveraged investor who tries to recover from a loss by adding more leverage is on the fastest path to account destruction.

When a Cash Account Is Better

For long-term investors running passive or low-turnover strategies, a cash account eliminates all the structural risks described above at essentially no cost. The settlement constraint is irrelevant if you are not recycling the same cash across multiple trades in a single day.

Investors who are below the $25,000 PDT threshold and want to trade actively actually benefit from a cash account, because it removes the PDT rule entirely. The settlement constraint is the constraint they must manage instead, which is a simpler and less dangerous one.

Anyone who has experienced a forced margin liquidation once rarely needs to be told twice. The psychological cost of being forced out of a position at the worst time, combined with the direct financial loss, is a powerful argument for removing the mechanism that enables it.

For more on how account types fit together, see the Investment Accounts & Brokerage Accounts hub.

Frequently Asked Questions

References

• FINRA: Investor Bulletin on Margin Accounts
• SEC: Margin: Borrowing Money to Pay for Stocks
• Federal Reserve: Regulation T