$900 in cash looks like room to wait for a stock to recover. But $700 is due for a household bill in five days.
Return to the 200-share position in Harbor Coffee, our fictional coffee business, bought partly with a loan. The $900 sits outside the account. You plan to hold through a fall to $50 before the bill comes due because you expect a rebound.
Can you keep every share without missing the bill? With borrowed money, the broker gets a say in how long you can wait.
Start with the cash deadline
Keep the margin lesson's $66 entry price, 200 shares and $6,600 loan. The outside cash, bill and $50 price fall are new teaching assumptions.
| Case input | Given | Status |
|---|---|---|
| Entry price | $66 per share | Year 3 cast |
| Shares / loan | 200 / $6,600 | Scenario |
| Stress price | $50 per share | Scenario |
| Outside cash | $900 | Scenario |
| Household bill | $700 in 5 days | Scenario |
| House rate | Unknown | Must verify |
These shares are your only brokerage holdings. No new cash arrives before the bill. Ignore interest, distributions, fees and taxes.
Here, risk of ruin means running out of the money or borrowing capacity needed to keep your plan going. That can happen while both the stock and your household still have value.
Find the missing broker term
At $50, your 200 shares are worth $10,000. Subtract the $6,600 loan and you have $3,400 of account equity: 34% of the shares' value.
Outside cash available for a deposit is $900 − $700 = $200. The bill has a claim on the rest.
The missing input is the house maintenance requirement: the minimum equity percentage your broker demands. The earlier 25% example cannot fill that blank. Try 35% and 40% to see why it matters.
The plan is still unproven. The smaller demand fits your spare cash; the larger one leaves you $400 short. These are deposit amounts; selling stock requires a different amount because it also shrinks the position.
Even the $100 deposit works only if it reaches the account before the broker sells. A lower price or a higher house rate can reopen the gap.
The disclosure explains the broker's powers; it cannot supply this broker's actual rate. A regulatory minimum cannot fill that blank either.
A forced exit changes the outcome
Continue the 40% case: suppose the broker sells all 200 shares at $50 before you deposit anything. The $10,000 proceeds repay the $6,600 loan, leaving $3,400 in the brokerage account.
Your separate $900 and the $700 bill are unchanged. The full sale at $50 is part of the test; a broker could sell fewer shares or get a different price.
If Harbor later returns to $66 while you stay in cash, the brokerage balance is still $3,400. Sold shares cannot take part in a rebound.
Funding liquidity risk is the risk of being unable to supply cash when it is due. A forced exit can be a cash problem even when your view of the business has not changed.
With short selling, the same check applies to collateral and the cost of returning shares. Short-interest and squeeze data may flag crowded positions; they cannot tell you whether your own cash will last.
LTCM ran out of room
Long-Term Capital Management borrowed heavily to profit from small price differences between similar securities. When those gaps widened during market turmoil, the fund lost 44% of its value in August 1998. Trading different instruments did not remove its need for fresh cash.
Federal Reserve History reports that on September 23, 1998, 14 financial firms agreed to supply about $3.6 billion of private capital. The Federal Reserve helped arrange the deal without lending its own money.
A promising valuation argument cannot pay a cash demand. The ability to wait has to be financed.
Write the decision and its limits
Use this survival checklist to put your answer in six lines:
- Obligation: Repay the $6,600 loan secured by the shares.
- Starting equity / exposure: $6,600 of your money supports $13,200 of stock.
- Stress outcome: $3,400 account equity at $50 a share.
- Cash available in time: $200 after reserving the $700 bill.
- Missing terms: The broker's house rate and response to a shortfall.
- Decision: Holding all 200 shares is unproven; at 40%, you are $400 short.
A different rate, more cash available in time or less debt would change the answer. A confident price target changes none of those dollars.
That is a complete answer: the holding plan is unproven, the house rate needs checking, and the $700 stays reserved for the bill.
Reducing the position or declining more borrowing can also be the result. A simple, unleveraged plan is a complete way to invest.
Match the check to the contract
For a long option, use options basics to separate the premium at risk from any share transaction created by exercise. The resulting stock position can lose more than the option's premium.
Stress an early exit using option pricing: the stock can move your way while the option loses value. For covered calls and cash-secured puts, identify the shares or cash assignment would require. Money reserved for the household bill cannot also back a put sale.
The optional branches add three checks; none is needed to finish this margin case:
- Sensitivity: Use the Greeks for small changes, and question whether those estimates still apply after a large move.
- Protection: With protective puts, match the floor and expiration to the need, then allow time to turn the position into spendable cash.
- Daily cash: For futures, check whether outside funds can meet settlement losses and collateral demands while the contract stays open.
In short
- A plan to wait needs cash that can arrive before a funding deadline.
- Money reserved for a bill cannot also cover a margin deposit.
- A regulatory minimum does not fix the broker's house rate or guarantee time to respond.
- A forced sale can make a temporary price decline a lasting investment loss.
- A conditional answer or a simpler investing plan is a successful finish.