An investor buys $20,000 of stock using $10,000 of their own cash and $10,000 borrowed from a broker. The maintenance margin requirement is 25%. At approximately what stock value will the broker issue a margin call?
A$15,000 — when the position has lost 25% of its original value
B$13,333 — when equity equals exactly 25% of the current security value
C$12,500 — when equity falls to half its original level
D$10,000 — when the position value equals the loan balance
The loan stays fixed at $10,000. Equity = security value − $10,000. The margin call triggers when equity / security value = 0.25. Solving: (V − 10,000) / V = 0.25 → V = $13,333. At this point the investor's $10,000 equity has shrunk to $3,333 (25% of $13,333). Note that option A makes the common error of applying the 25% to the original purchase price rather than the current security value. Option D would mean total equity wipeout, which the broker cannot wait for.
Question 2 Multiple Choice
During a broad market decline, why do margin calls tend to amplify price drops rather than absorb them?
AMargin calls require brokers to buy more stock as collateral, increasing demand and prices
BInvestors receiving margin calls must sell securities to meet the call, which further depresses prices and triggers more margin calls
CFalling prices increase the interest rate on margin loans, making borrowing more expensive and reducing new investment
DMargin calls cause investors to buy safer assets instead, draining liquidity from equity markets
The forced deleveraging spiral: falling prices reduce equity in leveraged accounts → margin calls are issued → investors must liquidate positions quickly → forced selling further depresses prices → more margin calls across other accounts. This feedback loop — not just individual risk — is why margin requirements are a macro-prudential regulatory tool. The 2008 financial crisis featured exactly this dynamic across mortgage-backed securities and other leveraged positions.
Question 3 True / False
A 2:1 leveraged position (50% equity, 50% borrowed) produces twice the percentage gain on equity compared to an unlevered position when the stock price rises.
TTrue
FFalse
Answer: True
Leverage amplifies returns symmetrically. If you invest $5,000 equity to control $10,000 of stock and the stock rises 10% to $11,000, your equity becomes $6,000 — a 20% return on your $5,000 investment. An unlevered investor who put $10,000 directly into the stock also has $11,000, a 10% return. The 2:1 leverage ratio exactly doubles percentage returns (and losses). This symmetry is the essential fact: leverage amplifies in both directions with equal force.
Question 4 True / False
A margin call is issued when a position's value falls below the initial margin requirement.
TTrue
FFalse
Answer: False
Margin calls are triggered by the maintenance margin requirement (typically 25–30%), not the initial margin requirement (50% under Reg T). The initial margin only applies at purchase — it sets the minimum equity needed to open the position. After that, the lower maintenance margin governs whether the position can stay open. This distinction matters: a position can lose significant value without triggering a margin call, as long as equity remains above the maintenance threshold. Conflating the two requirements leads to miscalculating when forced liquidation occurs.
Question 5 Short Answer
Why can a broad decline in asset prices trigger a cascade of margin calls that amplifies the decline beyond what the fundamental news would warrant?
Think about your answer, then reveal below.
Model answer: When prices fall, leveraged investors' equity (assets minus fixed loan balance) shrinks as a percentage of asset value. If equity falls below the maintenance margin threshold, the broker demands additional cash or will liquidate the position. Since many leveraged investors face calls simultaneously during a broad decline, they are all forced to sell — regardless of their own judgment about fair value. This coordinated forced selling depresses prices further, pushing more leveraged accounts below their maintenance thresholds and triggering another wave of calls. The spiral continues until enough positions are liquidated to restore solvency. This is not a market efficiently repricing assets; it is a mechanical feedback loop driven by the structure of leveraged lending.
This systemic dimension — the 'deleveraging spiral' — is why margin regulation is treated as a tool for financial stability, not just credit management. Higher margin requirements mean less leverage, smaller equity-to-debt ratios, and fewer accounts at risk of forced liquidation during a market stress event.