What it means
A cash investor pays for a security in full, whereas a margin investor deposits part of the purchase amount and borrows the rest through a margin account. The broker holds a secured claim against account assets and charges interest on the outstanding debit balance.
The investor still bears market risk on the entire position. Suppose an investor buys $10,000 of eligible stock with $5,000 cash and a $5,000 margin loan.
If the stock later sells for $12,000, $5,000 repays the loan and $7,000 remains before interest and costs, so the $2,000 gross gain is 40% of the investor's initial $5,000, compared with 20% on an all-cash $10,000 purchase. The same leverage works downward.
If that stock falls to $8,000, the loan still totals about $5,000 before interest and account equity is $3,000, so the $2,000 gross stock loss is 40% of the investor's initial cash. A deeper decline can consume the entire contribution and leave money still owed after a forced sale.
Initial margin and maintenance margin are different tests: initial rules govern the funds needed to open a position, while maintenance rules require enough equity relative to the current account value as prices move. FINRA describes a general minimum maintenance standard for stocks and warns that a broker may impose higher house requirements or change them.
Check the current rules and the account agreement for the actual security. A margin call occurs when the account lacks required equity.
The broker may demand funds or eligible securities, but an investor should not assume a notice or an extension will arrive before liquidation, because FINRA warns that firms can sell securities without contacting the customer first. The sale can occur at an unfavourable price and does not necessarily eliminate the debt.
Dividends or distributions on the purchased security do not cancel the loan automatically, and cash flows, taxes, interest, and broker treatment all affect the actual account balance. A sensible risk plan sizes the position against possible losses, loan interest, and the cash available for a call, and models a sharp overnight decline, not just a gradual fall that allows an orderly exit.
Even a good long-term investment can be sold at the wrong time when the financing is short-term and the account no longer meets requirements.
In practice
Real-world examples.
Example
An investor pays $4,000 and borrows $4,000 for $8,000 of shares. A 25% share-price fall reduces the shares to $6,000 and leaves about $2,000 equity before borrowing costs, a 50% decline in contributed capital.
Example
A portfolio rises 15% in a year, but the borrowed amount carries interest. The investor calculates a net return after that charge rather than reporting the leveraged market gain alone.
Example
A broker increases its house maintenance requirement on a volatile stock. The customer checks available equity and possible sale exposure rather than relying on an older minimum percentage.
Formula
Calculation
Account equity = current market value of securities minus margin loan balance, ignoring other account items. Equity percentage = equity divided by current market value. If stock worth $8,000 secures a $5,000 loan, equity is $8,000 - $5,000 = $3,000, or 3,000 / 8,000 = 37.5%. Interest accrual and other holdings change the actual account calculation; the required percentage depends on rules and the firm's terms.
To see how close a call can be, suppose a hypothetical 30% house maintenance requirement. The stock value P at which equity equals 30% satisfies P - $5,000 = 0.30P, so 0.70P = $5,000 and P = about $7,143, only about 10.7% below $8,000. Interest matters as well: at an assumed 8% a year, a $5,000 loan costs $400 a year, and the investor should check how dividends are credited and whether borrowing costs are deductible under the relevant tax rules rather than assuming the headline dividend yield pays for the loan.Case study
Seen in the real world.
Fictional example: Manager Sofia used $50,000 of cash and a $50,000 broker loan to purchase a diversified equity basket. Her model initially compared $100,000 of market exposure with only the expected upside. She revised it to show loan interest, a severe drawdown, and the broker's maintenance requirements.
After a market decline, the basket was worth $78,000 and the loan still stood near $50,000. Equity had fallen to roughly $28,000 before interest. Sofia held cash outside the account but learned that the broker could liquidate if its requirements were breached.
Watch out
Common mistakes.
- Calculating gains on the full position while forgetting loan interest, fees, and the possibility of losses beyond deposited funds.
- Treating the regulatory maintenance minimum as the only requirement, ignoring stricter or changing broker house rules.
- Assuming the broker must provide advance notice or time to add cash before it sells securities in a deficient account.
Questions
People also ask.
Do I own the securities bought on margin?
The investor holds the securities subject to the broker's secured loan and the margin agreement; ownership does not remove the loan or collateral obligations.
Can I lose more than my original cash?
Yes. A steep decline, accrued interest, or unfavourable forced sale can leave a debt after the initial contribution is exhausted.
Is a margin call always a phone call?
No. A broker may demand added equity but can also liquidate without first contacting the customer under the applicable agreement and rules.
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