Prospect theory in M&A: Do historical purchase prices affect merger offer premiums and announcement returns?

Prospect Theory suggests that when the pre-offer market price is below the historical purchase price, target shareholders may be reluctant to accept a merger offer, because it requires realizing nominal losses. In a sample of all U.S. public firm merger offers in 1990–2019, we find that the acquirer partially compensates target shareholders, including retail investors, for their losses via a higher offer premium. Consistent with Prospect Theory, the marginal compensation decreases with loss size and is higher in cash-only deals. We also show that the extra premium paid hurts (boosts) acquirer (target) shareholders' wealth.