Accretion/Dilution Analysis Explained: M&A Interview Must-Know

Accretion/Dilution Analysis: The M&A Concept You Must Master

Accretion/dilution analysis is one of the most important topics in M&A-focused investment banking interviews. If you are interviewing for any coverage or M&A group at Goldman Sachs, Morgan Stanley, J.P. Morgan, or an elite boutique like Centerview or PJT Partners, you need to know this concept cold.

At its core, accretion/dilution analysis answers a simple question: After an acquisition closes, will the acquirer's earnings per share (EPS) go up or down?

What Accretive and Dilutive Mean

• Accretive: The acquirer's pro forma EPS is higher than its standalone EPS after the deal closes. This is generally viewed positively by the acquirer's shareholders.
• Dilutive: The acquirer's pro forma EPS is lower than its standalone EPS after the deal closes. This is generally viewed negatively and may face pushback from the acquirer's board.

Important nuance: a deal being accretive does not necessarily mean it is a good deal, and a dilutive deal is not necessarily bad. A company could make a terrible acquisition at a low price (accretive but value-destroying) or a great strategic acquisition at a premium (dilutive in year one but highly valuable long-term). However, publicly traded acquirers pay close attention to EPS impact because it affects their stock price.

Step-by-Step Accretion/Dilution Walkthrough

Here is how to calculate accretion/dilution in an interview setting:

Step 1: Calculate the Acquirer's Standalone EPS

Start with the acquirer's net income and share count:

• Acquirer Net Income: $500M
• Acquirer Shares Outstanding: 100M
• Acquirer Standalone EPS: $5.00

Step 2: Calculate the Target's Net Income Contribution

Determine what the target adds to the combined company's earnings:

• Target Net Income: $100M

Step 3: Determine the Cost of the Acquisition

This depends on the deal structure:

All-Cash Deal:

• If financed with cash on hand, the cost is the foregone interest income (after tax) on that cash
• If financed with new debt, the cost is the after-tax interest expense on the new debt
• Example: $1B acquisition financed with debt at 5% interest, 25% tax rate = $1B x 5% x (1 - 25%) = $37.5M after-tax cost

All-Stock Deal:

• The cost is the dilution from new shares issued
• Example: $1B acquisition, acquirer's stock price is $50/share = 20M new shares issued
• New share count: 100M + 20M = 120M shares

Mixed Deal (Cash + Stock):

• Calculate the cost of each component separately

Step 4: Calculate Pro Forma EPS

All-Cash Deal (Debt Financed):

• Pro Forma Net Income = $500M + $100M - $37.5M = $562.5M
• Pro Forma Shares = 100M (unchanged)
• Pro Forma EPS = $5.625 (accretive by $0.625 or 12.5%)

All-Stock Deal:

• Pro Forma Net Income = $500M + $100M = $600M
• Pro Forma Shares = 120M
• Pro Forma EPS = $5.00 (neutral — EPS unchanged)

Step 5: Determine Accretion or Dilution

Compare pro forma EPS to standalone EPS:

• If Pro Forma EPS > Standalone EPS = Accretive
• If Pro Forma EPS < Standalone EPS = Dilutive

The P/E Arbitrage Shortcut

Here is the fastest way to determine accretion/dilution in an all-stock deal — and the insight interviewers love to hear:

In an all-stock deal with no synergies or premium, the deal is accretive to the acquirer if the acquirer's P/E ratio is higher than the target's P/E ratio.

Why? A higher P/E means the acquirer is using an "expensive" currency (its stock) to buy "cheaper" earnings. Each dollar of the target's earnings costs less in terms of EPS dilution than the acquirer's own earnings.

• Acquirer P/E: 20x, Target P/E: 15x — Accretive (buying cheap earnings with expensive stock)
• Acquirer P/E: 15x, Target P/E: 20x — Dilutive (buying expensive earnings with cheaper stock)
• Same P/E — Neutral

This is sometimes called P/E arbitrage or multiple arbitrage. In practice, large companies with high P/E multiples can acquire smaller companies with lower multiples and create immediate EPS accretion — which is one reason why serial acquirers trade at premium multiples.

Impact of Synergies

Synergies can turn a dilutive deal into an accretive one. There are two types:

Revenue Synergies

Cross-selling, geographic expansion, bundled product offerings. These are harder to achieve and typically discounted by 50-75% in models.

Cost Synergies

Headcount reduction, facility consolidation, procurement savings. These are more predictable and typically realized within 1-3 years.

In accretion/dilution analysis, you add the after-tax synergies to pro forma net income:

• If the deal is dilutive by $20M but you expect $50M in after-tax cost synergies, the deal becomes accretive by $30M with synergies included.

Interviewers may ask: "How much in synergies would you need to make this deal break even from an EPS perspective?" This is a straightforward algebra problem — solve for the synergy amount that makes pro forma EPS equal standalone EPS.

Cash Deal vs. Stock Deal: When Is Each Preferred?

Cash deals are preferred when:

• Interest rates are low (debt financing is cheap)
• The acquirer has significant cash on hand
• The acquirer's stock is undervalued (issuing stock would give away too much value)
• The acquirer wants to retain 100% of the upside

Stock deals are preferred when:

• The acquirer's stock is highly valued (using "expensive" currency)
• The acquirer wants to share risk with target shareholders
• The deal is too large to finance with debt
• The acquirer wants to preserve its balance sheet capacity

Common Interview Questions

Q: "Company A (P/E of 15x) acquires Company B (P/E of 10x) in an all-stock deal. Is the deal accretive or dilutive?"

A: Accretive. The acquirer has a higher P/E than the target, so it is buying cheaper earnings with expensive stock.

Q: "What are the key drivers of accretion/dilution?"

A: The four key drivers are: (1) the relative P/E ratios of the acquirer and target, (2) the mix of cash vs. stock consideration, (3) the cost of debt financing, and (4) expected synergies.

Q: "A deal is 5% dilutive in year 1. Should the acquirer walk away?"

A: Not necessarily. Short-term dilution can be acceptable if the strategic rationale is compelling and synergies will make the deal accretive by year 2-3. Many transformative deals are initially dilutive. The acquirer should evaluate long-term value creation, not just year-1 EPS impact.

Q: "If interest rates rise, does that make cash deals or stock deals more attractive?"

A: Higher interest rates increase the after-tax cost of debt financing, making cash deals (funded with debt) relatively less attractive and stock deals relatively more attractive, all else equal.

How This Connects to Merger Models

Accretion/dilution analysis is the simplified version of what a full merger model calculates. In practice, you would build a detailed merger model that includes purchase price allocation (goodwill, intangible asset write-ups), transaction costs, financing structure, synergy phase-in, and multi-year pro forma projections. But the core concept is identical: does the combined company generate more or less EPS than the acquirer on a standalone basis?

Master This for Your Interviews

Accretion/dilution is tested in nearly every M&A-focused interview. Practice walking through the analysis verbally — interviewers do not expect you to build a spreadsheet, but they expect you to articulate the logic clearly and handle follow-up questions confidently.

IB Flash features targeted M&A interview questions, including accretion/dilution scenarios with varying deal structures, so you can practice until this analysis becomes second nature. Try the DCF Calculator to build intuition for how valuation inputs drive deal outcomes. Also review our guides on enterprise value vs. equity value and how to walk through an LBO — both are closely tested alongside accretion/dilution.