Event-driven investing focuses on corporate events that create temporary mispricings in securities. Unlike momentum or value strategies that rely on broad market patterns, event-driven trades are anchored to specific, identifiable catalysts with known timelines.
Types of Event-Driven Strategies
Merger Arbitrage
When Company A announces an acquisition of Company B at $50 per share, Company B’s stock typically jumps to $48-49 — not $50. The $1-2 gap represents the merger spread, which compensates for the risk that the deal fails.
Merger arbitrage involves buying the target at $48 and waiting for deal closure at $50. The spread is small (2-4% per deal) but relatively predictable, and deals typically close within 3-6 months, generating annualized returns of 6-15%.
Key risks include:
- Deal breakage — regulatory blocks, financing failures, or buyer remorse can cause the target to drop 20-40%
- Extended timelines — antitrust reviews can delay closings, reducing annualized returns
- Interest rate sensitivity — higher rates increase the opportunity cost of tied-up capital
Spinoff Investing
When a company spins off a division into a separate public entity, the newly independent stock often underperforms initially, then outperforms over the following 12-24 months.
Why? Several mechanical reasons:
- Index fund selling — the spinoff may not meet index inclusion criteria, forcing passive funds to sell
- Institutional mandates — the spinoff may be too small or in the wrong sector for the parent company’s shareholders
- Lack of coverage — analysts take time to initiate coverage on new entities
- Management incentives — spinoff management teams typically receive significant equity compensation, aligning their interests with shareholders
Research by Joel Greenblatt and others has documented that spinoffs outperform the market by 10-15% annually in the two years following separation.
Activist Investing
Activist investors acquire significant positions in undervalued companies, then push for changes: board seats, strategic alternatives, capital returns, or operational improvements. Following disclosed activist positions can be profitable, as the campaign itself often serves as a catalyst for value realization.
The key is selectivity — not all activist campaigns succeed. Focus on situations where:
- The activist has a strong track record
- The thesis is straightforward (e.g., excess cash that should be returned, an obvious divestiture)
- Management is responsive rather than entrenched
Building an Event-Driven Portfolio
Effective event-driven portfolios share several characteristics:
Diversification across events: Hold 15-30 positions across different event types to reduce the impact of any single deal breaking.
Position sizing by probability: Size merger arb positions based on the estimated probability of deal completion. High-probability deals get larger allocations; speculative situations get smaller ones.
Hedging systematic risk: Use index hedges to isolate event-specific returns from broad market moves. A merger arb portfolio should generate returns whether the market is up or down.
Calendar awareness: Event-driven opportunities cluster around earnings seasons, year-end tax selling, and index rebalancing dates. Plan capital allocation accordingly.
The Edge
Event-driven strategies work because they exploit structural inefficiencies — forced selling by index funds, regulatory complexity that deters generalists, and time horizons that are too short for long-only investors but too long for day traders. The edge comes from expertise in process and probability, not from predicting market direction.