Understanding how margin works in options trading is crucial for managing risk and optimizing capital efficiency. On OKX, the margin system for both single-currency and cross-currency options follows a tiered, dynamic model based on position size, order type, and market conditions. This guide breaks down the margin calculation rules for options trading on OKX, including order margin, position margin, and maintenance margin, with real-world examples to help traders make informed decisions.
How OKX Calculates Options Margin: Tiered System Overview
OKX applies a tiered margin model for options sellers, meaning the required margin increases proportionally with the total number of contracts held or pending in sell orders. The margin coefficient scales upward based on three components:
- Sell-side open positions
- Active sell limit orders
- New sell limit orders
Higher tiers correspond to higher margin coefficients, promoting responsible risk management. For illustration in this article, we assume a margin coefficient of 1.02 at Tier 2.
👉 Discover how OKX's dynamic margin system enhances trading efficiency and risk control.
1. Order Margin: Funds Frozen When Placing Orders
Order margin refers to the collateral temporarily locked when placing a limit order, ensuring sufficient funds are available upon execution.
Opening Positions
(1) Buy-to-Open Order Margin
When buying options, the formula is:
Buy-to-Open Margin = (Limit Price × Contract Multiplier + Fee per Contract) × Number of ContractsExample 1:
You want to buy 100 BTCUSD call options (BTCUSD-20200515-8500-C) at 0.0475 BTC each.
- Contract multiplier: 0.1 BTC
- Trading fee (LV1): 0.02% → 0.00002 BTC per contract
Calculation:
= (0.0475 × 0.1 + 0.00002) × 100
= 0.477 BTC
(2) Sell-to-Open Order Margin
For selling options, the formula accounts for potential risk exposure:
Sell-to-Open Margin = max(Single Position Margin – (Limit Price × Multiplier) + Fee, Minimum Order Margin × Multiplier) × ContractsMinimums by Pair:
- BTCUSD/ETHUSD: 0.1 × multiplier
- EOSUSD: 0.125 × multiplier
Example 2:
Sell 100 BTC call options at 0.06 BTC.
- Mark price: 0.0575 BTC
- Underlying futures mark price: $5900
- Strike price: $6000 → In-the-money by $100
Single contract margin:
= [max(0.1, 0.15 – 100/5900) × 1.02 + 0.0575] × 0.1
= 0.01932 BTC
Sell order margin:
= max(0.01932 – (0.06 × 0.1) + 0.00002, 0.1 × 0.1) × 100
= max(–0.04066, 0.01) → capped at 0.01 × 100 = 1 BTC, but actual result rounds to 1.334 BTC
Closing Positions
(3) Sell-to-Close Order Margin
Used when closing a long position by selling:
Sell-to-Close Margin = max(Fee per Contract – (Limit Price × Multiplier), 0) × ContractsExample 3:
Sell to close 100 put options at 0.0755 BTC.
- Fee: 0.00002 BTC
- (Limit price × multiplier): 0.0755 × 0.1 = 0.00755
= max(0.00002 – 0.00755, 0) × 100 = 0 BTC
(4) Buy-to-Close Order Margin
Used when covering a short position:
Buy-to-Close Margin = max(Limit Price – (Position Margin / Multiplier) + Fee, 0) × Multiplier × ContractsExample 4:
Buy back 100 call options at 0.05 BTC to close.
Using prior position margin of 0.01932 BTC:
= max(0.05 – (0.01932 / 0.1) + 0.02%, 0) × 0.1 × 100
= max(–14.3%, 0) → zero margin required
2. Position Margin: Collateral for Open Short Positions
This is the actual margin held while maintaining a short options position.
(1) Long Position Margin = 0
Buyers only pay the premium; no additional margin is required.
(2) Call Option Sellers (Short Calls)
BTCUSD & ETHUSD:
Position Margin = [max(0.1, 0.15 – ITM Depth / Futures Mark Price) × Coefficient + Mark Price] × Multiplier × ContractsEOSUSD:
Position Margin = [max(0.125, 0.2 – ITM Depth / Futures Mark Price) × Coefficient + Mark Price] × Multiplier × ContractsExample 5:
Sell 50 BTC calls at $6K strike, futures at $59K, mark price = $6K → $1K ITM depth
= [max(0.1, 0.15 – 1/59) × 1.02 + 0.0575] × 0.1 × 50
= ~$966 worth in BTC
(3) Put Option Sellers (Short Puts)
BTCUSD & ETHUSD:
Position Margin = [max(0.1×(1+Mark Price), 0.15 – ITM Depth / Futures Price) × Coeff + Mark Price] × Mult × ContractsEOSUSD:
Uses 0.125 and 0.2 thresholds respectively.
Example 6:
Sell 100 BTC puts at $85K strike, futures at $864K → $14K ITM depth
Mark price: 2.25% of BTC → ~$225 equivalent
Calculation yields: ~$1,589 in collateral
In-the-Money (ITM) Depth: For calls, it’s (Strike – Futures Price); for puts, (Futures Price – Strike). Greater depth means higher risk and margin.
👉 See how deep ITM exposure affects margin requirements on OKX options trading platform.
3. Maintenance Margin: Minimum Equity to Avoid Liquidation
If your account equity drops below this level, forced deleveraging may occur.
(1) Long Positions: Maintenance Margin = 0
(2) Short Call Maintenance
- BTCUSD/ETHUSD:
(0.075 × Coeff + Mark Price) × Mult × Contracts - EOSUSD: Replace with
0.125
Example 7:
Sell 1K call contracts → Maintenance = (0.075×1.02 + 575bps)×Mult×Contracts → ~$134 total
(3) Short Put Maintenance
- BTCUSD/ETHUSD:
[0.075×(1+Mark Price)×Coeff + Mark Price] × Mult × Contracts - EOSUSD: Use
±adjustments accordingly
Example 8:
Sell deep OTM puts at low volatility → lower maintenance (~$1,545 for same contract size)
Frequently Asked Questions (FAQs)
Q: Why is order margin sometimes higher than the option premium?
A: Because OKX accounts for worst-case scenarios — especially for sellers — where the option could go deep in-the-money, requiring more collateral than the received premium.
Q: Do buyers need to post margin?
A: No. Buyers only pay the premium upfront; their maximum loss is capped, so no ongoing margin is required.
Q: How does tiering affect my trading?
A: As your sell-side exposure grows (open positions + active sell orders), you move into higher tiers with increased margin coefficients, reducing leverage but improving system stability.
Q: What happens if I fall below maintenance margin?
A: The system triggers forced deleveraging to prevent insolvency — your position may be partially or fully closed without manual intervention.
Q: Is there a difference between single-currency and cross-currency options?
A: Yes — single-currency options use the same asset for settlement and margin (e.g., BTC-denominated), while cross-currency pairs may involve different base/settlement assets, affecting conversion and risk calculations.
Core Keywords
- OKX options margin calculation
- Options position margin
- Sell-to-open margin rules
- Maintenance margin for options
- Tiered margin system
- In-the-money depth calculation
- Order margin freeze
- Options trading risk management
By mastering these mechanics, traders can better anticipate capital needs and avoid unexpected liquidations. Whether you're hedging or speculating, understanding how OKX calculates margin across options strategies empowers smarter decision-making.