OKX Portfolio Margin vs Multi-Currency Margin: When Hedging Helps

The one-paragraph answer

Portfolio margin lowers margin when, and only when, a book contains offsetting exposures inside the same risk unit. Multi-currency margin lowers margin when the book is small, unhedged, or hedged across units, because it charges each instrument by position tier and does not try to stress-test the combination. The two modes are not tiers of the same ladder; they are different measurements of risk, and either can produce the smaller number.

What each mode actually computes

OKX’s account-mode comparison sets out the difference in one table. The four modes themselves — spot, futures, multi-currency margin and portfolio margin — are described in the OKX account modes guide.

Multi-currency margin

• Margin is calculated per instrument from position tiers: MMR = position size × contract size × MMR of the tier.
• Positions are valued in USD so collateral can be pooled across currencies.
• PnL hedging between different cryptocurrencies valued in USD is supported.
• Long options sit in isolated margin; only short options count toward free margin.

Portfolio margin

• Derivatives are grouped into risk units by underlying.
• Each unit is stress-tested across scenarios, and the maintenance margin is the maximum loss:

MMR_risk_unit = Max( Max(MR1, MR2, MR6) + MR3 + MR4 + MR5, MR7 )

where MR1 is a spot shock, MR2 theta decay, MR6 an extreme move, MR3 basis risk, MR4 vega risk, MR5 interest rate risk, and MR7 a minimum charge.

• Account MMR is the sum of the risk units plus account-level borrowing margin.
• Initial margin is IMR = 1.3 × Max(positive-delta derivatives MMR, negative-delta derivatives MMR, total derivatives MMR) + borrowing IMR.
• In the spot-derivatives offset variant, the delta of spot holdings can be placed into the matching USDT-margined or crypto-margined risk unit.

The formulas explain the behaviour. Multi-currency margin is additive: each position contributes its tier MMR, and diversification does not reduce the total. Portfolio margin is a maximum over scenarios: if one leg gains when another loses inside the same unit, the stressed loss is smaller than the sum of the legs.

The offset is narrower than it looks

The phrase “risk offsetting is supported” invites a wrong conclusion. OKX qualifies it twice:

1. “The effect of offsetting margin is evaluated within the same risk unit, and risks cannot be offset between different risk units.”
2. In the spot-derivatives variant, spot assets are included only when their delta is assigned to the corresponding unit — BTC spot into the BTC-USD or BTC-USDT unit, for example.

So the hedges that portfolio margin recognises are structural, not statistical:

A trader who is hedged economically but not structurally gets the stress-test apparatus without the offset. That is the worst of both modes: more complexity, no margin relief.

The numbers OKX publishes

OKX’s comparison includes a small-position example. The same assets and positions produce:

• Multi-currency margin: MMR = 6.14 USD
• Portfolio margin, derivatives-only: MMR = 67.08 USD

The portfolio figure is roughly eleven times the multi-currency figure. The reason is visible in the formula: the portfolio calculation applies a minimum charge and stress scenarios to a book whose positions are too small for any offset to matter, while the tier-based calculation simply reads small position sizes off a table.

For large books the comparison reverses. OKX states that users with large-scale assets — it gives “value of positions in both directions > 5 million USD, depending on the hedging strategy” as a reference — hedged strategies and spot holdings benefit from lower MMR and more flexible capital utilisation. It also states that market makers, professional traders and institutional traders can receive 75% or 50% lower MMR and IMR in portfolio margin.

The crossover is the whole decision. It is not a setting to adopt because it sounds more advanced.

A decision test

Run this before switching.

1. List every position by risk unit, not by asset class. A BTC-USD perpetual and a BTC-USDT perpetual are separate units.
2. Ask whether the loss-making leg and the gain-making leg are in the same unit. If not, portfolio margin cannot offset them, and the stress-test minimum charge applies.
3. Compute both. OKX’s comparison points to a position builder for simulation; the formulas above are enough for an order-of-magnitude check. The maintenance margin and margin calls guide explains what the resulting MMR does to the liquidation distance.
4. Check the eligibility threshold — net assets above 10,000 USD.
5. Re-run the test after the book changes shape. A mode that was cheaper for a hedged book can become more expensive once the hedge is lifted, and the switch is not automatic.

Why this is not a repeat of the risk-calculation article

The earlier guide on this site — how OKX computes portfolio-margin risk — explains the MR factors and the maximum-loss logic inside a unit. This article answers a different question: given a book, which account mode produces the lower margin requirement, and what has to be true for the advanced mode to help. The answer turns on unit membership and book size, not on the arithmetic of the stress test.

Risk note

Mode rules, formulas, the 10,000 USD threshold and the 6.14/67.08 example were read from OKX’s account-mode comparison on 2026-10-28. Margin parameters, risk-unit groupings and eligibility rules can change, and a mode switch can alter liquidation behaviour as well as margin. The figures are OKX’s illustrative examples, not a quote for any account.