Merger arbitrage
What is Merger arbitrage?
Merger arbitrage invests in announced corporate transactions, commonly buying a target below offered consideration and sometimes hedging the acquirer's securities.
Deal portfolios require exposure limits by regulator, acquirer, financing source, sector, and common market factor. Several transactions can fail together after a policy shift or credit closure. Investors should analyze manager behavior during broken deals, not only annual win rate. Returns reported on deployed capital can also overstate investor experience when substantial cash remains idle or leverage finances the spread book. Historical analysis should include withdrawn transactions, revised consideration, hedging losses, legal expenses, taxes, borrow costs, and the full time required to redeploy capital after resolution.
How the spread works
The target usually trades below deal value because completion takes time and remains uncertain. Spread compensates for financing, timing, conditions, and failure risk. Stock deals require exchange-ratio analysis and often a short acquirer hedge. Dividends, elections, collars, competing bids, and regulatory remedies alter payoff.
Example
A cash offer is $50 while target trades at $47. Completion in six months produces $3 before costs, but failure can return price toward $30. The apparently small upside is paired with asymmetric downside. Expected return must weight completion, delay, revised terms, and break price rather than annualize $3 mechanically.
Research process
Review legal agreement, financing, shareholder votes, antitrust, foreign approvals, litigation, material-adverse-change clauses, termination rights, and expected timeline. Compare management statements with primary filings. Position sizing should reflect correlated deal breaks and shared regulatory exposure, not treat every announced transaction as independent.
Return drivers
Returns arise from accepting deal risk, information analysis, portfolio construction, and occasional improved bids. Cash yield and borrow affect stock deals. Spreads can widen even as completion probability remains high because funding or risk appetite changes. Manager skill must be assessed after failed deals, hedging, leverage, and transaction costs.
Risks and practical checklist
Risks include deal failure, delay, repricing, regulation, financing, litigation, vote, borrow, liquidity, and leverage. Build completion and break scenarios, verify consideration and dates, monitor filings, and cap correlated exposure. Do not confuse a signed agreement with certainty or use the unaffected price as a guaranteed downside floor.
Sources and further reading
- Investment Products, Investor.gov, U.S. Securities and Exchange Commission