Strategic Performance Management and Business Valuation · Valuation in Mergers and Acquisitions

Exchange Ratio and Share Swap Ratio Calculation in Mergers

Updated 11 October 2026 · Fact-checked

The exchange ratio (swap ratio) is the number of acquirer shares given for each share of the target. Compute it from a chosen basis: EPS, market price, book value or intrinsic value, or from a weighted average of these. Then find the merged EPS, P/E and market price to test who gains.

Understand Exchange Ratio and Share Swap Calculations

In a stock-for-stock merger, the acquirer pays target shareholders with its own shares. The exchange ratio tells you how many acquirer shares each target share receives. A ratio of 0.5 means 1 target share gets half an acquirer share.

The ratio is a bargain over value. You pick a basis of value per share for each company and divide the target's figure by the acquirer's. Common bases are EPS, market price per share, book value per share and intrinsic (fair) value per share. When one basis is not enough, you give each basis a weight and take a weighted average.

The ratio you compute is a starting point. After the merger, you check the effect on the combined firm: new shares issued, combined earnings, EPS after merger, and the market price if the P/E is assumed. Each side wants its own EPS or value not to fall. This is where the exam asks for your recommendation.

Keep two ideas apart. The ratio based on market price gives target holders the same market value they held before, with no premium. A ratio based on EPS gives them the same share of earnings. If the two companies have different P/E ratios, the choice moves value between the groups.

Key rules to remember

Exchange ratio on market price: ER = Market price per share of target ÷ Market price per share of acquirer; Gives target holders the same market value, with no premium. Add any premium to the target price first.
Exchange ratio on EPS: ER = EPS of target ÷ EPS of acquirer; Equates earnings contribution per share. Use the same EPS basis for both.
Exchange ratio on book value: ER = Book value per share of target ÷ Book value per share of acquirer; Book value per share = Net worth available to equity ÷ Number of equity shares.
Weighted exchange ratio: ER = Σ (weight × ratio on each basis), with weights summing to 1; Use the weights given in the question. If none are given, state your assumption.
New shares issued: New shares = Target shares × ER; Total shares after merger = Acquirer shares + New shares.
EPS after merger: Merged EPS = (Earnings of acquirer + Earnings of target + synergy) ÷ Total shares after merger; Add synergy only if the question states it.
Market price after merger: Price = Merged EPS × P/E ratio assumed; The P/E is usually the acquirer's, or a stated combined P/E.
Equivalent EPS for target holder: Equivalent EPS = Merged EPS × ER; Compare with the target's old EPS to see the gain or loss per target share.

How to solve Exchange Ratio and Share Swap Calculations questions

Use the same sequence for any swap ratio question. It keeps the working clean and easy to mark.

1List the data for both companies: earnings, shares, EPS, market price, P/E, book value or net worth.
2Work out the missing per-share figures (EPS, book value per share, market price) from the data given.
3Find the exchange ratio on the basis asked. If several bases and weights are given, find each ratio and then the weighted ratio.
4Compute new shares issued: target shares × ER. Add to the acquirer's existing shares.
5Compute combined earnings (add synergy if given) and the merged EPS.
6Apply the stated P/E to find the market price after merger and the market capitalisation if asked.
7Compute each side's gain or loss: the acquirer's EPS or price change, and the target holder's equivalent EPS or value received.
8Write a one-line recommendation naming who gains and whether the ratio is acceptable.

Quickest way: Per-share table first, then ratio

When to use it: Use it for MCQs and for long questions with three or more data lines for each company.

Draw two columns, Acquirer and Target, with rows for EPS, price, book value per share and shares.
Fill every cell before any calculation. Most errors come from a wrong per-share figure.
Divide target by acquirer in the row asked to get the ratio.
For merged EPS, use total earnings ÷ (acquirer shares + target shares × ER).
Check the answer: target holders' equivalent EPS = merged EPS × ER. If the ratio is EPS based, the acquirer's EPS should not change when there is no synergy.

Common mistakes in Exchange Ratio and Share Swap Calculations

Dividing acquirer by target instead of target by acquirer.
Students think of the acquirer as the 'bigger' number and put it on top.
Fix: The ratio is acquirer shares per target share. Target value goes on top, acquirer value at the bottom.
Using total earnings or total market value instead of per-share values.
The question lists totals, and students rush into the division.
Fix: Convert to per share first. If you use totals, the ratio is a value ratio, not a share ratio.
Adding the target's shares to the acquirer's shares in the merged EPS.
Students forget the target's shares are cancelled and replaced by new shares.
Fix: Total shares = acquirer shares + (target shares × ER).
Ignoring the weights or averaging the ratios with equal weights.
The weights are in a separate line, and students overlook them.
Fix: Multiply each ratio by its weight and add. Check that the weights sum to 1 or 100%.
Using the wrong P/E to find the market price after merger.
Both companies have a P/E, and the question does not always spell out which one applies.
Fix: Use the P/E the question states for the merged firm. If none is given, use the acquirer's P/E and state this assumption.
Giving figures but no conclusion.
Students stop once the numbers are done.
Fix: End with a sentence comparing before and after for each set of shareholders and say whether the ratio is fair.

Worked examples

Example 1

Alpha Ltd and Beta Ltd plan a merger. Alpha: earnings ₹60,00,000, 10,00,000 shares, market price ₹90. Beta: earnings ₹20,00,000, 5,00,000 shares, market price ₹36. Find (a) the exchange ratio on EPS, (b) the exchange ratio on market price, (c) the merged EPS if the ratio on market price is used and there is no synergy.

Show the solution

Alpha EPS = 60,00,000 ÷ 10,00,000 = ₹6. Beta EPS = 20,00,000 ÷ 5,00,000 = ₹4.
(a) ER on EPS = 4 ÷ 6 = 0.6667 Alpha shares per Beta share.
(b) ER on market price = 36 ÷ 90 = 0.4.
(c) New shares = 5,00,000 × 0.4 = 2,00,000. Total shares = 12,00,000.
Combined earnings = 60,00,000 + 20,00,000 = ₹80,00,000.
Merged EPS = 80,00,000 ÷ 12,00,000 = ₹6.67 (approx.).
Check: Alpha's EPS rises from ₹6 to ₹6.67. Beta holders' equivalent EPS = 6.67 × 0.4 = ₹2.67, below their old ₹4.

Answer: (a) 0.6667 (b) 0.4 (c) Merged EPS ≈ ₹6.67. At the market price ratio, Alpha holders gain EPS and Beta holders lose EPS, because Beta has a lower P/E (9 against 15).

Example 2

Gamma Ltd will absorb Delta Ltd. Gamma: 8,00,000 shares, EPS ₹10, book value per share ₹80, P/E 12. Delta: 4,00,000 shares, EPS ₹8, book value per share ₹50. The ratio is to be the weighted average of EPS ratio and book value ratio with weights 2 and 1 respectively. Find the exchange ratio, the merged EPS with no synergy, and the market price after merger at Gamma's P/E.

Show the solution

EPS ratio = 8 ÷ 10 = 0.8.
Book value ratio = 50 ÷ 80 = 0.625.
Weighted ER = (0.8 × 2 + 0.625 × 1) ÷ 3 = 2.225 ÷ 3 = 0.7417.
New shares = 4,00,000 × 0.7417 = 2,96,667 (approx.). Total shares = 10,96,667.
Earnings: Gamma = 8,00,000 × 10 = ₹80,00,000. Delta = 4,00,000 × 8 = ₹32,00,000. Total = ₹1,12,00,000.
Merged EPS = 1,12,00,000 ÷ 10,96,667 = ₹10.21 (approx.).
Market price = 10.21 × 12 = ₹122.5 (approx.), against the earlier ₹120 (10 × 12).
Delta holders' equivalent EPS = 10.21 × 0.7417 = ₹7.57, against ₹8 earlier.

Answer: Exchange ratio ≈ 0.7417. Merged EPS ≈ ₹10.21. Market price ≈ ₹122.5. Gamma holders gain slightly; Delta holders' equivalent EPS falls from ₹8 to about ₹7.57.

Exam tips

Write the per-share table first. Marks are often given for correct EPS, book value and price figures even if the later steps go wrong.
Say which basis and which weights you use. If the question is silent, state your assumption in one line.
Show the check: equivalent EPS of target holders = merged EPS × ER. It proves the working and gives the comparison for your conclusion.
In MCQs, watch the direction of the ratio and the share count. The common wrong options come from inverting the ratio.
Always finish with a recommendation in the case-based questions: who gains, who loses, and whether the ratio is acceptable.

Practice questions from Valuation in Mergers and Acquisitions

Exchange Ratio and Share Swap Calculations in other exams

The same ground in other exams, if you are preparing for more than one or want another angle on it.

Exchange Ratio and Share Swap Calculations: frequently asked questions

What is the exchange ratio in a merger?

It is the number of acquirer shares issued for each share of the target company. It is found by dividing the target's value per share by the acquirer's value per share on the chosen basis.

Which basis should I use for the swap ratio?

Use the basis the question states. If it gives several bases with weights, compute each ratio and take the weighted average. If nothing is stated, market price is common and you should say that you assumed it.

How do I find EPS after merger?

Add the earnings of both companies (plus synergy if given) and divide by the acquirer's old shares plus new shares issued. New shares are the target's shares multiplied by the exchange ratio.

How do I find the market price after merger?

Multiply the merged EPS by the P/E ratio stated for the combined firm. If no P/E is given for it, use the acquirer's P/E and state the assumption.