Understand margin calls and square-off

1. First principles: what is margin?

Let us define the pieces from scratch so nothing is memorised blindly.

Position value $V$ = current market value of what you hold.
Borrowed amount $B$ = money the broker lent you (fixed at entry until you pay/close).
Equity $E$ = your actual ownership stake: $E = V - B$

2. Deriving the maintenance-margin condition

The broker sets a maintenance margin — a minimum fraction $m$ of the position value that your equity must always cover.

Why this step? The broker doesn't care about your entry price — only about right now. If your equity dips below a slice of the current value, the loan is under-collateralised.

Solve for the price that triggers the call

Let you own $Q$ shares, borrowed $B$ , current price $P$ . Then $V = QP$ and $E = QP - B$ .

Set the trigger equality $E = mV$ : $QP - B = m\,QP$ $QP(1-m) = B$ $\boxed{P_{\text{call}} = \dfrac{B}{Q(1-m)}}$

Why this step? We isolated $P$ to find the exact price at which the cushion hits its legal minimum. Below $P_{\text{call}}$ you get called.

3. Square-off

Two common triggers:

Margin shortfall: equity keeps falling and you don't add funds → broker liquidates.
Time-based (intraday): MIS/intraday products are auto squared-off before market close (e.g., ~3:20 PM) because leverage was only meant for the day.

Figure — Understand margin calls and square-off

4. Worked examples

Worked example Example 1 — Finding the margin-call price

You buy 100 shares at ₹500 (V = ₹50,000). Broker lends ₹35,000 (B), so your margin = ₹15,000. Maintenance margin $m = 25\%$ . At what price do you get called?

Step 1 — identify pieces. $Q=100$ , $B=35000$ , $m=0.25$ . Why? We need $B, Q, m$ to plug into $P_{\text{call}}$ .

Step 2 — apply formula. $P_{\text{call}} = \frac{B}{Q(1-m)} = \frac{35000}{100 \times 0.75} = \frac{35000}{75} = ₹466.67$ Why? This is the price where equity $= 25\%$ of value exactly.

Step 3 — verify. At ₹466.67: $V=46{,}667$ , $E=46{,}667-35{,}000=11{,}667$ , and $0.25\times46{,}667=11{,}667$ . ✓ Why? Confirms $E = mV$ — the knife-edge. Below ₹466.67 → margin call.

5. Common mistakes (steel-manned)

7. Active recall — flashcards

What is equity in a leveraged position?

Your true stake,

E = V - B

(current value minus borrowed amount).

When does a margin call trigger?

When equity falls below the maintenance requirement:

E < mV

Formula for the margin-call price?

P_{\text{call}} = \dfrac{B}{Q(1-m)}

What is a square-off?

Broker forcibly closing your open position to protect their loaned capital or at an intraday time cut-off.

Two triggers for square-off?

(1) Unmet margin shortfall; (2) time-based intraday auto square-off before close.

Is a margin call a penalty?

No — it's a request to restore your own margin cushion; no fine if met in time.

Does square-off execute at your entry price?

No — at the current market price, often at a loss.

How do you cure a margin call?

Add funds (raise

E

) or reduce the position (lower

B

V

) until

E \ge mV

Why does higher leverage cause earlier calls?

Larger

B

raises

P_{\text{call}}

, so a smaller price drop crosses the trigger.

Recall Feynman: explain to a 12-year-old

Imagine a friend lends you money to buy a bigger bag of candy, but only if you also put in some of your own coins as a safety pile. If the candy's price drops, your safety pile gets small. Your friend says "add more coins!" — that's a margin call. If you don't, your friend takes the candy and sells it to get their money back before your pile disappears — that's a square-off. They're just making sure they never lose their money — your loss stays yours.

Connections

Leverage and Margin Trading
Intraday vs Delivery (MIS vs CNC)
Stop-Loss Orders
Position Sizing and Risk Management
Order Types and Execution
Overnight Gap Risk

Concept Map

Hinglish (regional understanding)

Intuition Hinglish mein samjho

Dekho, jab tum leverage (broker se udhaar) leke trade karte ho, to broker ka paisa laga hota hai, aur tumhara apna paisa (margin) ek safety cushion ki tarah kaam karta hai. Tumhari equity = position ki current value minus udhaar ( $E = V - B$ ). Jab tak yeh equity broker ke minimum requirement se upar hai ( $E \ge mV$ ), sab theek hai.

Jaise hi price girti hai aur tumhari equity is minimum se neeche chali jaati hai, broker margin call deta hai — matlab "bhai apna cushion top-up karo, paise daalo ya position chhoti karo." Yeh koi penalty nahi hai, sirf request hai ki apna hissa restore karo. Agar tum ignore karte ho, ya intraday (MIS) ka time cut-off (lagbhag 3:20 PM) aa jaata hai, to broker square-off kar deta hai — tumhari position khud band kar deta hai, current market price par, taaki unka paisa safe rahe aur tumhara loss tumhare margin tak hi rahe.

Sabse important formula: margin-call price $P_{\text{call}} = \frac{B}{Q(1-m)}$ . Jitna zyada udhaar ( $B$ ) loge, utna hi upar yeh price hoga, matlab thodi si girawat par hi call aa jaayega. Isliye position size aise rakho ki $P_{\text{call}}$ realistic swings se kaafi neeche ho. Yaad rakho: pehle CALL, phir CLOSE — aur trigger hamesha current price par hota hai, tumhare entry price par nahi.

1. First principles: what is margin?

2. Deriving the maintenance-margin condition

Solve for the price that triggers the call

3. Square-off

4. Worked examples

5. Common mistakes (steel-manned)

6. Forecast-then-Verify

7. Active recall — flashcards

Connections

Concept Map

Hinglish (regional understanding)

Test yourself — How to Trade — Execution & Platforms

Connections