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Parth Parekh
STAGE 06RISKEXECUTION PLANE
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Margin and charges before anyone sizes

Pre-trade risk answers one question with real money attached: what will this proposed book actually cost to hold, and can we hold it? It runs before sizing, and it is the one check allowed to stop the path.

WHAT I BUILTRISK

Built here.

  • 01

    A margin service that ingests the exchange's daily SPAN risk parameter files across every product family and computes span, exposure and premium components for a proposed position.

  • 02

    Basket margining that nets a multi-leg book properly, including the calendar-spread term across expiries — a hedged spread is not four times a single leg, and sizing off the naive sum wastes capital.

  • 03

    A what-if workbench: propose a book, see the margin and the charge profile before committing, under both proprietary and retail cost models.

  • 04

    Scheduled refreshes matching the exchange's intraday publication cycle, with an in-memory cache and a persisted fallback so a restart does not lose the day's risk arrays.

  • 05

    Commodity coverage alongside equity derivatives.

WHAT IT SURVIVESFAILURE MODES

Failure modes.

  • Risk files arriving late or in a changed shape, where the previous good set is retained rather than failing to a zero margin.
  • Contract metadata that disagrees between upstream dumps — identifiers are resolved as either integer or string because real dumps are not type-consistent.
  • A stale utilisation screen, which is acceptable; a stale gate answer, which is not.

Sizing without margin is how a desk finds out at 09:20 that it cannot afford the position it just entered.

STACKON THIS STAGE