Definition
Directional exposure means your position profits if the event goes one way and loses if it goes the other way. A directional trader holding YES on "Fed cuts rates in June" profits if the Fed cuts rates and loses if it doesn't. Directional exposure is the defining feature of speculative trading — and the thing that arbitrage is specifically designed to eliminate.
Zero directional exposure in arbitrage
A perfect complement arbitrage trade has zero directional exposure. Holding YES (cost $0.47) on Platform A and NO (cost $0.51) on Platform B for the same event:
- If YES wins: YES pays $1.00, NO pays $0.00. Total received: $1.00. Profit: $1.00 − $0.98 = $0.02
- If NO wins: YES pays $0.00, NO pays $1.00. Total received: $1.00. Profit: $1.00 − $0.98 = $0.02
The profit is identical regardless of outcome. Zero directional exposure.
How directional exposure enters arbitrage
Directional exposure creeps in through execution failures:
- Failed Leg 2: Leg 1 fills but Leg 2 never executes. You hold a pure directional position.
- Partial fill mismatch: Leg 1 fills for 60 units, Leg 2 fills for 100 units. The excess 40 units of Leg 2 are directional.
- Resolution mismatch: The two contracts have subtly different resolution criteria — one pays $1.00 and the other also pays $1.00 (or both $0.00). The complement property breaks.
Managing directional exposure
The circuit breaker is the primary tool: when directional exposure is detected (failed or mismatched leg), it unwinds the position immediately. Arbitrage Agent checks leg symmetry continuously and triggers the circuit breaker when it detects an imbalance.