Is This Deal Accretive or Dilutive? The IB Interview Shortcut

"Is this deal accretive or dilutive?" is one of the highest-frequency M&A technicals in IB interviews. Accretive means pro forma EPS goes up versus the acquirer's standalone EPS. Dilutive means it goes down. You do not always need a full merger model in the room. You need the intuition, the shortcuts, the list of things that break those shortcuts, and enough modeling reps that you can defend the answer when a VP pushes.

Definitions in one breath

Accretive: Pro forma EPS > Acquirer standalone EPS
Dilutive:  Pro forma EPS < Acquirer standalone EPS
Flat:     Pro forma EPS ≈ standalone EPS

Banks care because public acquirers are graded on EPS optics in the market, even though strategic value is broader than EPS. A deal can be strategically smart and still dilutive near term. Your job in an interview is to separate those ideas cleanly.

Why EPS moves at all

Pro forma EPS is roughly:

Pro forma NI = Acquirer NI + Target NI + after-tax synergies − after-tax deal costs
Pro forma shares = Acquirer shares + new shares issued (stock deals)
Pro forma EPS = Pro forma NI / Pro forma shares

Cash/debt deals change the numerator through interest expense (or lost interest income). Stock deals change the denominator through new shares, and can also change the numerator if there are other adjustments. Mixed deals do both.

All-stock shortcut (know this cold)

In a pure stock deal with no synergies and simple assumptions:

If Acquirer P/E > Purchase P/E of Target  →  usually accretive
If Acquirer P/E < Purchase P/E of Target  →  usually dilutive

Why the shortcut works

P/E is price per unit of earnings. If your stock trades at 20x and you buy earnings at 15x using your shares, you are issuing "expensive" currency to buy "cheaper" earnings. More earnings are added per unit of dilution than your own shares implied. That tends to raise EPS.

Worked example

• Acquirer NI = $500M, shares = 100M, EPS = $5.00, price = $100 → P/E = 20x
• Target purchase equity value = $750M, target NI = $50M → purchase P/E = 15x
• 100% stock: new shares issued ≈ 750 / 100 = 7.5M
• Combined NI = 550M (ignore synergies/taxes complications)
• Combined shares = 107.5M
• Pro forma EPS ≈ 5.12 → accretive

You will not always get this much detail in an interview. The directional P/E comparison still gets you there fast.

When the stock shortcut breaks

• Large control premium raises purchase P/E above the "cheap earnings" story
• Synergies / costs to achieve change Year 1 NI a lot
• Different tax rates, noncontrolling interests, or preferred
• Huge PPA amortization hits GAAP EPS
• Earnouts and deferred payments distort "purchase P/E"
• Buyer issues stock when its own earnings are temporarily depressed (P/E looks artificially high)

Cash / debt shortcut

For a cash deal financed with debt:

Target earnings yield ≈ 1 / Purchase P/E
After-tax cost of debt = Interest rate × (1 − tax rate)

If earnings yield > after-tax debt cost → tends to be accretive
If earnings yield < after-tax debt cost → tends to be dilutive

Worked example

• Purchase P/E = 10x → earnings yield = 10%
• Debt rate = 6%, tax = 25% → after-tax cost = 4.5%
• 10% > 4.5% → accretive directionally

Intuition: you borrow at 4.5% after tax to buy an earnings stream yielding 10%.

Cash on hand version

If you use existing cash, compare earnings yield to after-tax forgone interest on that cash (often low). That is why cash-on-hand deals can look very accretive mechanically, even when strategically expensive, until you account for liquidity and rating agency optics.

Mixed consideration

When the deal is part cash and part stock, blend the costs:

• Stock portion: opportunity cost tied to 1 / acquirer P/E
• Debt/cash portion: after-tax interest / forgone interest
• Compare blended cost to target earnings yield

Bankers show tables across 100% cash → 100% stock for EPS, leverage, and ownership. In interviews, ask for the mix if it is not given. Do not invent a fake precise EPS change.

Ownership point students forget

More stock consideration means target shareholders own more of the combined company. That can be good or bad depending on whether you want them aligned or you want full upside. Accretion is not the only lens.

Purchase accounting and Year 1 dilution traps

Even when the strategic P/E story says accretive, Year 1 GAAP EPS can be dilutive because of:

• Inventory step-up through COGS (temporary)
• PP&E and intangible write-ups → higher D&A
• Transaction fees and financing fees
• Synergy timing (costs first, benefits later)
• Retention payments and integration opex

A strong interview sentence:

"Directionally the P/E relationship says accretive, but I would still run a merger model for financing mix, synergies, and purchase accounting. Year 1 can look worse than the steady state."

45-second answer template

"Accretion means pro forma EPS rises versus the buyer alone. In an all-stock deal I compare buyer P/E to the purchase P/E on the target: higher buyer P/E tends to be accretive because you issue richer currency for cheaper earnings. In a cash deal I compare the target's earnings yield to the after-tax cost of debt. Synergies help accretion; high premiums, slow synergy ramp, and step-up amortization can flip a deal dilutive in Year 1 even if the strategic story is fine."

Mini drills (do these out loud)

1. Buyer 25x, target purchase 18x, 100% stock → likely accretive
2. Buyer 12x, target purchase 16x, 100% stock → likely dilutive
3. Purchase P/E 8x, debt 7% pre-tax, tax 25% → yield 12.5% vs after-tax debt ~5.3% → likely accretive
4. Same as 3, but Year 1 synergies are zero and PPA amortization is large → may still be dilutive near term
5. 50/50 cash-stock: explain what you need to know before calling it

Full model checklist when they push past the shortcut

If an interviewer wants the long version:

1. Standalone acquirer EPS
2. Offer value and consideration mix
3. New shares issued
4. New interest expense / forgone interest
5. Target NI included
6. After-tax synergies and costs to achieve
7. Incremental D&A from write-ups
8. Pro forma NI / pro forma shares
9. Compare to standalone EPS
10. Sensitize premium, mix, and synergies

That is what a Harborview-style merger case trains.

How this ties to cash vs stock judgment

Cash deals often look better for EPS and let the buyer keep upside. Stock deals share upside/risk with sellers and can protect the balance sheet. Mixed deals balance leverage, ownership, and EPS optics. If your accretion answer ignores those tradeoffs, it sounds like a formula monkey.

Practice plan

Day 1: Memorize stock and cash shortcuts with two numeric examples each
Day 2: Add premium and synergy overlays verbally
Day 3: Build one merger model and toggle 100% cash / 100% stock / mixed
Day 4: Explain why Year 1 and Year 2 accretion can differ
Day 5: Mock interview with a friend changing one assumption each time

The shortcut gets you through first rounds. The model gets you through a skeptical VP in a superday.