BULK Exchange Margin: Portfolio Margin, Cross-Margin, and Isolated Margin Explained

BULK Exchange uses portfolio margin by default. Instead of evaluating each position’s risk independently, the risk engine evaluates your entire portfolio as a single unit — accounting for correlations between positions. Hedged portfolios use significantly less margin than unhedged ones.

Documented efficiency claim: Up to 70% margin reduction on hedged portfolios.

Portfolio Margin: How It Actually Works

On most exchanges (and on Hyperliquid), margin is calculated per position. Long BTC requires X margin. Short ETH requires Y margin. Total margin = X + Y. Positions don’t interact.

On BULK Exchange, the risk engine computes a correlation-adjusted effective notional for the entire portfolio. Positions that offset each other’s risk are treated as a combined position — which requires less margin than the sum of their parts.

The 9-Regime HMM

The underlying model is a 9-regime Hidden Markov Model:

3 market regimes: Bearish × Neutral × Bullish 3 volatility regimes: Low × Medium × High

The model classifies each market into one of the nine regime combinations. Each combination has a different lambda surface — the three-dimensional function mapping leverage, market impact, and volatility regime to a margin requirement.

No discrete tier jumps. Margin requirements use bilinear interpolation between regime states. There are no cliff edges where crossing a threshold suddenly doubles your margin requirement.

The Correlation Offset

The practical result of portfolio margin: positions that hedge each other require less total margin.

Example — BTC/ETH hedged pair (correlation ~0.85):

The exact BULK requirement depends on current regime classification and the correlation coefficient at the time of the trade. At 70% maximum efficiency, the hedged pair requires ~30% of what per-position margin would demand.

Freed capital = deployable in additional trades, held as buffer against drawdown, or withdrawn.

Sub-Accounts as Isolation Boundaries

Each sub-account on BULK Exchange runs a completely independent portfolio margin evaluation.

What this means in practice:

• A leveraged long BTC position in sub-account 1 doesn’t affect margin in sub-account 2
• A liquidation event in sub-account 3 doesn’t touch sub-accounts 1 and 2
• You can run completely separate risk profiles across strategies without one strategy’s performance affecting another

This is the institutional use case: separate accounts for different strategies, each with independent risk, all under one master wallet and aggregating volume for fee tier purposes.

Isolated Margin: When to Use It

Isolated margin routes a specific order to a per-instrument isolated account instead of the main portfolio.

How to activate: Add i=true to any order. An isolated account is created automatically on first use. One instrument per isolated account.

Use cases:

• High-conviction directional trade where you want to cap maximum loss
• Experimental positions on volatile assets (memecoins via BIP-1, new listings)
• Positions you don’t want affecting your main portfolio margin
• Teaching yourself BULK’s mechanics without risking your main account

How to size isolated positions: The maximum you can lose equals the capital in the isolated account. Size accordingly.

Portfolio Margin vs. Isolated Margin: The Decision

The Lambda Surface

The lambda surface is the core mathematical object of BULK’s portfolio margin engine. It’s a 3D function:

Inputs:

• Leverage (position size / account equity)
• Market impact (position size relative to ADV)
• Volatility regime (from the HMM classifier)

Output: Margin requirement as a continuous function of these three inputs.

Why continuous matters: most exchanges use tier tables. If your leverage crosses a tier boundary, margin jumps discretely. BULK’s bilinear interpolation means small changes in leverage produce small, proportional changes in margin — no cliff edges.

Cascade Adjustment

The risk engine runs a 2-round iteration to account for liquidation cascade effects.

The problem without cascade adjustment: A position looks well-margined in isolation, but closing it (due to margin breach) could destabilize other correlated positions, requiring further liquidations.

BULK’s solution: Before flagging a liquidation, the engine estimates the price impact of liquidating the position and recalculates whether the portfolio would still be solvent after the cascade. If so, the cascade effect is acceptable. If not, the engine may act earlier to prevent the cascade.

This is the “positions appearing well-margined in isolation but causing systemic risk” problem, directly addressed per the architecture documentation.

Comparing to Hyperliquid’s Margin

Frequently Asked Questions

What is portfolio margin on BULK Exchange? Portfolio margin evaluates your entire account as a single risk unit, using correlation between positions to reduce the total margin requirement for hedged portfolios. BULK claims up to 70% margin efficiency on correlated hedged positions vs. per-position margin.

How does BULK Exchange calculate margin? BULK uses a 9-regime Hidden Markov Model (3 market regimes × 3 volatility regimes) to classify each market. A 3D lambda surface maps leverage, market impact, and volatility regime to a continuous margin requirement with no discrete tier jumps.

What is isolated margin on BULK Exchange? Adding i=true to any order routes it to a per-instrument isolated account. Isolated positions have a fixed maximum loss (the capital in the isolated account) and don’t affect the main portfolio margin.

How much more capital efficient is BULK’s portfolio margin vs. Hyperliquid? BULK documents up to 70% margin efficiency on hedged portfolios. Hyperliquid uses per-position tiered margin with no correlation adjustment. On a hedged BTC/ETH pair, this difference can free 50–70% of capital that would otherwise be locked as margin on Hyperliquid.

Try portfolio margin live → early.bulk.trade

Last updated: June 3, 2026. Source: BULK Exchange architecture documentation