What Is an Exchange Ratio?
In a stock-for-stock transaction, the acquirer pays target shareholders with newly issued shares of its own stock, and the exchange ratio sets the conversion rate. It is calculated as the offer value per target share divided by the acquirer's share price. If an acquirer trading at $50 agrees to pay $75 of value per target share, the exchange ratio is 1.5x, meaning each target share converts into 1.5 acquirer shares.
The ratio also determines the ownership split of the combined company. Multiplying the ratio by the target's share count gives the new shares issued, and target holders' stake equals those new shares divided by the pro forma total. Bankers cross-check that split against each side's contribution of revenue and earnings in a contribution analysis.
Fixed Versus Floating Exchange Ratios
A fixed exchange ratio locks the number of acquirer shares per target share at signing, so the dollar value of the consideration rises and falls with the acquirer's stock price during the months before closing. Target shareholders bear the downside if the acquirer's shares slide but capture the upside if they rally, and the pro forma ownership split stays constant.
A floating exchange ratio, also called a fixed value structure, guarantees a set dollar amount per target share and adjusts the number of shares delivered based on the acquirer's price near closing, often measured over a 10- or 20-day volume-weighted average. Here the acquirer bears the market risk, since a falling stock price forces it to issue more shares and accept more dilution. Many deals bound either structure with a collar.
Why the Exchange Ratio Matters
Negotiating the exchange ratio is effectively negotiating relative valuation. In mergers of equals, where little or no premium is paid, the ratio is often derived from the two companies' recent average trading prices and debated line by line against contribution and ownership math. A small change in the ratio can shift billions of dollars of value between the two shareholder bases.
The ratio also drives merger arbitrage. Once a fixed ratio deal is announced, arbitrageurs buy the target and short the acquirer in proportion to the ratio, capturing the spread if the deal closes. For interview preparation, candidates should be able to compute a ratio from an offer premium and explain who holds price risk under fixed and floating structures.
