Most event-driven positions fail not because the thesis is wrong, but because the timeline slips. Mechanism: Corporate events — regulatory approvals, deal closes, restructuring completions — are subject to delays that erode the economics of a time-sensitive position. That is why event-driven investing requires explicit hedging of time risk, not just directional risk. Market translation: A merger expected to close in Q2 that slips to Q4 can halve the annualized return of the spread, even though the deal eventually completes. Failure mode: The mistake is sizing an event position based on the announced timeline without building in a delay buffer. Review question: Before sizing up, identify whether the edge comes from cash flow, volatility, timing or balance-sheet structure. The point is not to memorize the label. The point is to know what variable is actually doing the work.