Module V — Margin Survival Engineering

Status: outline. Lecture body not authored. Phase: 3 SURVIVAL

The true risk of independent accounts. Central risk is not modelled as ordinary volatility but as a first-passage problem.

T_SO = inf { t : Equity(t) ≤ so × UsedMargin(t) }

Unique process — Neutral in P&L, fragile in survival

The sum of equities can stay stable while one account approaches liquidation.

Contents (curriculum): UsedMargin; FreeMargin; MarginLevel; stop-out; margin call; Slack; T_SO; first passage; margin fixed vs mark-to-market; stop-out policy; partial liquidation; sequential liquidation; negative balance protection.

Lab: a move where account A loses, account B wins, the aggregate is ≈ neutral, and account A hits stop-out.