Learn mark-to-market settlement

What Is Mark-to-Market Settlement?

This happens every trading day until the contract expires or is closed.

Why MTM Exists: The Problem It Solves

Without MTM: Imagine you go long1 Nifty futures contract at ₹18,000. The market crashes to ₹15,000 over two weeks. You owe ₹150,000 in losses [(18,000 - 15,000) × 50lot size]. On expiry, you might not have that money—you default, and the exchange (or the counterparty) eats the loss.

With MTM: Every day the market drops₹100, the exchange immediately debits ₹5,000 from your account and credits the short seller. If your margin falls below the maintenance margin, you get a margin call and must add funds today. If you can't, your position is liquidated. The exchange never lets losses pile up invisibly.

Why this matters: MTM transforms counterparty risk (risk that your opponent won't pay) into margin risk (risk you can't meet daily margin requirements). The exchange becomes the central counterparty, and daily cash settlement makes the system robust.

Deriving the Daily MTM Cash Flow

First Principles: What Changes Each Day?

On Day 0, you enter a long futures position at price $F_0$. The exchange sets this as your reference price.

On Day 1, the settlement price is $F_1$. Your position has moved by:

For a long position (you agreed to BUY at $F_0$):

• If $F_1 > F_0$: The contract is now worth more (you can "sell" it at $F_1$ instead of $F_0$). You profit.
• If $F_1 < F_0$: The contract is worth less. You lose.

Your Day 1 cash flow (per unit):

$\text{MTM P\&L} = (F_1 - F_0) \times \text{Contract Multiplier}$

If positive → exchange credits your margin account.
If negative → exchange debits your margin account.

Day 2 reference price becomes $F_1$, not $F_0$. So Day 2 P&L is $(F_2 - F_1) \times \text{Multiplier}$, and so on.

Multi-Day Cumulative P&L

Over $n$ days, your cumulative P&L is the sum of daily MTM:

$\text{Total P\&L} = \sum_{i=1}^{n} (F_i - F_{i-1}) \times M$

This telescopes:

Key insight: Even though cash changes hands daily, the cumulative P&L equals what it would be if you settled only at the end. MTM doesn't create or destroy value; it redistributes cash flow timing and enforces margin discipline.

Example 1: Long Nifty Futures with Daily MTM

Setup:

• You go long 1 lot of Nifty futures at ₹18,000 on Day 0
• Lot size = 50
• Initial margin deposited = ₹1,000
• Maintenance margin = ₹75,000

Step-by-step reasoning:

Day 1:

• Settlement moves from 18,000 → 18,200 (+200 points)
• MTM P&L = $(18,200 - 18,000) \times 50 = +₹10,000$
• Your margin account: ₹1,00,000 + ₹10,000 = ₹1,10,000
• Why this step? The exchange calculates your profit based on today's closing price vs. yesterday's reference Since you're long and price rose, you win; the short party's account is debited ₹10,000 and yours is credited.

Day 2:

• Settlement 18,200 → 18,100 (-100)
• MTM P&L = $(18,100 - 18,200) \times 50 = -₹5,000$
• Margin: ₹1,10,000 - ₹5,000 = ₹1,05,000
• Why? Price fell, you lose₹5,000. The reference resets to 18,100 for tomorrow.

Day 3:

• 18,100 → 17,800 (-300)
• MTM = $-300 \times 50 = -₹15,000$
• Margin: ₹1,05,000 - ₹15,000 = ₹90,000
• Still above maintenance margin (₹75,000), so no margin call.

Day 4:

• 17,800 → 17,500 (-300)
• MTM = $-₹15,000$
• Margin hits exactly ₹75,000 (maintenance margin)
• Margin call issued: You must deposit additional funds to bring margin back to initial margin (₹1,00,000), or the exchange will liquidate your position.

Cumulative P&L check:

• Entry: 18,000, Current: 17,500
• Total P&L = $(17,500 - 18,000) \times 50 = -₹25,000$
• Margin account: ₹1,00,000 - ₹25,000 = ₹75,✓ matches the table

Example 2: Short Position MTM

Setup:

• Short 1 contract at $80/barrel
• Contract size = 100 barrels
• Initial margin = $5,000

Day 1:

• Price drops 80 → 78 (-$2)
• You're short: You agreed to SELL at $80. If price falls, you profit (you can "buy back" cheaper).
• MTM P&L = $(80 - 78) \times 100 = +$200$
• Why? For shorts, the formula is $(F_{\text{old}} - F_{\text{new}}) \times M$. Price decrease → short profits.
• Margin: $5,000 +$200 = $5,200

Day 2:

• Price jumps 78 → 82 (+$4)
• MTM P&L = $(78 - 82) \times 100 = -$400$
• Margin: $5,200 -$400 = $4,800
• Why? Price rose; shorts lose. You agreed to sell at $80, but now the market is at$82—your position is underwater by $2/barrel from entry.

Cumulative check:

• Entry $80, current$82
• Total loss for short = $(80 - 82) \times 100 = -$200$
• Margin: $5,000 -$200 = $4,800 ✓

The Margin Account Mechanics

$\text{Margin}_{t} = \text{Margin}_{t-1} + \text{MTM P\&L}_{t}$

Where:

• $\text{Margin}_{t-1}$ = balance before today's settlement
• $\text{MTM P\&L}_{t}$ = $(F_t - F_{t-1}) \times M$ for longs, $(F_{t-1} - F_t) \times M$ for shorts

Margin call trigger:

You must deposit:

Why this structure? The initial margin is a buffer. The maintenance margin is the red line. The gap between them allows for normal daily volatility without constant margin calls. Once you hit maintenance, you must top up to initial—this ensures the exchange always has a cushion before your losses become the exchange's problem.

Common Mistakes & Steel-manning

Why it feels right: You see cash leaving your account daily when you're losing, so it seems like MTM is "costing you extra."

The steel-man: It's rational to worry about cash flow. If you have₹1,00,000 locked in margin and prices move against you, you need additional cash immediately—even if you're confident the market will recover. This is a real liquidity constraint.

The fix: MTM doesn't change your economic P&L. Whether cash moves daily or at expiry, your profit/loss is still $(F_{\text{final}} - F_{\text{entry}}) \times M$. MTM only changes when cash moves and enforces that you can't let losses run beyond your margin. Think of it as "pay-as-you-lose" vs. "pay-at-the-end"—the total bill is the same, but the timing protects the system.

Why it feels right: You have a strong thesis. The market dropped temporarily; you know it'll recover by expiry. Why liquidate at a loss?

The steel-man: This confidence might be justified. Forced liquidation at the worst moment can lock in losses that would have been avoided if you could hold through volatility.

The fix: The exchange doesn't know your thesis. From its perspective, every defaulted trader once thought "it'll come back." Margin rules are non-negotiable. The solution: size your position so that even adverse moves don't hit your maintenance margin. If you can't afford daily volatility, your position is too large. Futures are leveraged; respect the leverage.

Formula insight:

Example: If Nifty daily volatility is ±200 points and you can tolerate 3 bad days before margin call, ensure:

Worked Example3: Cumulative MTM Over a Week

• 1 Gold futures at $2,000/oz
• Contract size = 100 oz
• Initial margin = $10,000

Daily MTM formula (long position):

Day 1: $(2,020 - 2,000) \times 100 = +2,000$2,000$**Day 2:**$(2,010 - 2,020) \times 100 = -1,000$1,000$ (reference was yesterday's 2,020)
Day 3: $(2,030 - 2,010) \times 100 = +2,000$2,000$
And so on.

Cumulative MTM on Day 5:

Direct calculation:

Why track both? Daily MTM shows cash flow volatility (you need liquid funds). Cumulative MTM shows your actual economic position. Both matter: one for operations, one for strategy.

The Settlement Price: How It's Determined

Why not just the last trade? The last trade could be a tiny lot at an outlier price (manipulation risk). A VWAP smooths out noise and represents true market consensus.

Example: Nifty futures trade at 18,000, 18,010, 18,005 18,015 in the last minute. A single1-lot trade at 18,100 happens at 3:2959 PM. If the exchange used that, everyone's MTM would swing wildly on a fluke trade. Instead, VWAP might be ~18,008, reflecting actual liquidity.

MTM vs. Physical Delivery Settlement

Key distinction: Even commodity futures that allow physical delivery (e.g., crude oil) still have daily MTM until expiry. Physical delivery is a separate final settlement event—you still get marked-to-market every day leading up to it.

Active Recall Challenges

At the end of the match, you've already been paying and receiving money all along, so the final settlement is just a small adjustment. That's mark-to-market! In futures trading, the exchange does this every single day—if your bet (position) is winning, you get cash; if losing, you pay cash. This way, no one can disappear with a huge debt at the end. You settle a little bit every day, so it's always fair and safe.

Money Transfers Move daily

Margin Trigers Matter: If your margin hits the floor, you must add more or you're out the door.

Visual: Picture a seesaw where cash flows from losers to winners every sunset—the exchange is the fulcrum, keeping it balanced daily.

Connections

• 5.1.01-Futures-contracts-basics — MTM enforces the obligations created by futures contracts
• 5.1.03-Margin-requirements — MTM determines when margin calls trigger
• 5.1.05-Basis-and-convergence — Daily settlement price affects basis tracking
• 5.2.01-Hedging-with-futures — MTM cash flow impacts hedge liquidity planning
• 5.3.02-Clearing-house-role — The clearing house is the mechanism that executes MTM

Summary

Mark-to-market settlement is the daily reconciliation of futures P&L. Every day:

1. The exchange fixes a settlement price
2. Calculates $(F_{\text{today}} - F_{\text{yesterday}}) \times \text{Contract Size}$
3. Moves cash: credits winners, debits losers
4. Resets tomorrow's reference price

This prevents counterparty default risk and enforces margin discipline. Your cumulative P&L equals what it would be with final settlement, but the cash flow timing is accelerated. If your margin account falls below maintenance margin, you face a margin call—add funds or get liquidated.

MTM is the heartbeat of futures markets: it keeps the system alive by ensuring losses never silently accumulate.

#flashcards/stock-market

What is mark-to-market settlement? :: The daily process where the exchange calculates profit/loss on open futures positions based on the settlement price, debits losers' accounts, credits winners' accounts, and resets the reference price for the next day.

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Hinglish (regional understanding)