Accretion Dilution Analysis: The EPS Test in M&A
Accretion dilution analysis measures whether an acquisition raises or lowers the buyer's EPS. Get the P/E rule, financing test, and a worked example.
Jun 6, 2026 · 8 min read
Accretion dilution analysis measures whether an acquisition will raise or lower the acquirer's earnings per share (EPS) after the deal closes. You combine the two companies' net incomes, account for the new shares, debt, or cash used to fund the purchase, then compare the resulting pro forma EPS to the buyer's standalone EPS. If pro forma EPS is higher, the deal is accretive; if it is lower, the deal is dilutive. The fast version skips the full model: compare the acquirer's P/E to the target's, and weigh the after-tax cost of each financing source against the target's earnings yield. This is one of the most tested topics in M&A interviews, so the quick test matters as much as the math.
TL;DR
- Accretive means pro forma EPS rises versus the buyer's standalone EPS; dilutive means it falls.
- Quick rule: in an all-stock deal, buying a higher-P/E target with lower-P/E stock is usually dilutive (Street of Walls example: 11.0x buyer, 13.0x target).
- Cost of stock equals the earnings yield, 1 divided by the buyer's P/E multiple, per Breaking Into Wall Street.
- After-tax cost of cash and debt both equal the interest rate times (1 minus the tax rate).
- Accretion is not value creation: a deal can lift EPS while destroying value, so never conflate the two.
What is accretion dilution analysis?
Accretion dilution analysis is the test investment bankers run to estimate how a merger changes the acquirer's EPS. According to Street of Walls, you build a pro forma income statement that combines both companies' earnings, then divide by the new pro forma share count to get pro forma EPS. An increase in EPS is accretion; a decrease is dilution. The analysis is a screening tool, run before terms are finalized, to gauge whether a deal helps or hurts reported earnings. It is widely used because public-company management and shareholders watch EPS closely, even though EPS impact and economic value creation are separate questions.
How does the EPS test actually work?
The EPS test combines the buyer's and target's net income, adjusts for financing effects, and divides by the new share count. Start with the two companies' standalone net incomes. Add expected synergies if any. Subtract the after-tax cost of any new debt interest, and subtract the after-tax interest the buyer gives up by spending cash. Then count the shares: if the buyer issues stock, the pro forma share count rises by the number of new shares.
Because the pro forma earnings combine both income statements, the analysis also depends on understanding how the three financial statements link, since new debt and share counts flow through the model. In the Street of Walls all-stock example, the acquirer has EPS of 3.25 dollars, a P/E of 11.0x, and 1,000 shares, for earnings of 3,250. The target has EPS of 3.75 dollars, a P/E of 13.0x, and 300 shares, for earnings of 1,125. To buy the target, the acquirer issues 409 new shares, lifting the pro forma count to 1,409. Combined earnings of 4,375 divided by 1,409 shares gives a new EPS of 3.10 dollars, down from 3.25. The deal is dilutive.
What is the quick P/E rule of thumb?
The quick rule for an all-stock deal compares the two P/E multiples: if the acquirer's P/E is higher than the target's, the deal is accretive, and if it is lower, the deal is dilutive. The logic is that the acquirer is effectively swapping its own expensively-valued shares for the target's cheaper earnings, or the reverse. In the Street of Walls case the buyer trades at 11.0x and the target at 13.0x, so the lower-multiple buyer purchasing a higher-multiple target with stock produces dilution, exactly as the rule predicts. This shortcut works only for pure stock deals with no synergies. The moment cash or debt enters the mix, you switch to the cost-of-financing comparison below, because the P/E rule alone no longer captures the full picture.
How do cash, stock, and debt financing change the answer?
Each financing source has a cost, and the deal is accretive only when the target's earnings yield exceeds the weighted cost of how you pay for it. Per Breaking Into Wall Street, the after-tax cost of cash is the foregone interest rate times (1 minus the buyer's tax rate), the after-tax cost of debt is the debt interest rate times (1 minus the tax rate), and the cost of stock is 1 divided by the buyer's P/E multiple. You blend these by the percentage of each used, compare the result to the target's yield (its net income over the equity purchase price), and conclude: higher seller yield means accretive, lower means dilutive.
| Financing source | After-tax cost | Typically the |
|---|---|---|
| Cash on hand | Foregone interest rate × (1 − tax rate) | Cheapest |
| New debt | Debt interest rate × (1 − tax rate) | Middle |
| New stock | 1 ÷ buyer's P/E multiple (earnings yield) | Most expensive |
Because cash and debt usually cost only a few percent after tax while a 12x P/E implies an 8.3 percent equity cost, cash deals are most often accretive and stock deals most often dilutive. The earnings yield from a P/E of 11.3x, for instance, is 1 divided by 11.3, or about 8.9 percent, per Breaking Into Wall Street.
Why is accretion not the same as value creation?
Accretion measures EPS, not value, so a deal can lift EPS while still destroying shareholder value. A buyer can fund an acquisition with cheap debt, push pro forma EPS higher, and yet overpay so badly that the economic return falls below its cost of capital. EPS rises because the math of low-cost financing against the target's earnings yield is favorable, but that says nothing about whether the price paid was justified by the target's future cash flows. This is the trap interviewers set: candidates who say "the deal is accretive, so it creates value" get corrected. Accretion is an accounting outcome driven by financing mix and relative multiples. Value creation depends on price versus intrinsic worth, which is why a full DCF and comparable company analysis sit alongside, not inside, the accretion test.
Frequently Asked Questions
What makes a deal accretive versus dilutive?
A deal is accretive when pro forma EPS exceeds the buyer's standalone EPS and dilutive when it falls below. The drivers are the relative P/E multiples, the financing mix, synergies, and the interest or foregone-interest cost of cash and debt. In an all-stock deal, a higher-P/E buyer acquiring a lower-P/E target is accretive; reverse the multiples and it turns dilutive.
Why are cash deals usually more accretive than stock deals?
Cash and debt have a low after-tax cost, often a few percent, while issuing stock costs the buyer its earnings yield, 1 over its P/E. A company at 12x P/E has roughly an 8.3 percent cost of equity, far above after-tax debt or cash costs. Because the target's yield more easily clears the cheaper hurdle, cash and debt financing tends to be accretive while stock financing tends to be dilutive.
How do you calculate pro forma EPS?
Combine both companies' net incomes, add after-tax synergies, then subtract the after-tax cost of any new debt interest and the after-tax interest foregone on cash spent. Divide that combined adjusted net income by the pro forma share count, which is the buyer's shares plus any new shares issued to fund the deal. The result is pro forma EPS, which you compare to the buyer's standalone EPS.
Does accretion mean the acquisition was a good deal?
No. Accretion only tells you EPS went up; it says nothing about whether the buyer overpaid. A heavily debt-financed deal can be accretive yet still destroy value if the price exceeds the target's intrinsic worth. Interviewers test this distinction deliberately, so separate the EPS effect from the value question and never equate the two.
What is the breakeven analysis in accretion dilution?
Breakeven analysis finds the offer price, or the mix of financing, at which pro forma EPS exactly equals the buyer's standalone EPS, leaving the deal neither accretive nor dilutive. Street of Walls frames it as asking at what price the transaction becomes breakeven. Above that price the deal turns dilutive, and below it the deal turns accretive, which helps bankers frame the range of terms a buyer can offer.
How do synergies affect accretion dilution?
Synergies add to combined net income, which raises pro forma EPS and pushes a deal toward accretion. Cost synergies, like eliminating duplicate overhead, flow through after tax and directly lift the numerator in the EPS calculation. A deal that looks dilutive on a standalone-earnings basis can flip to accretive once realistic synergies are included, which is why the value of synergies is heavily negotiated and stress-tested in the model.
Sources
- Street of Walls, "Merger Model: Accretion/Dilution Analysis": https://www.streetofwalls.com/articles/investment-banking/recruiting-interviewing/merger-model-accretion-dilution/ (checked June 2026)
- Breaking Into Wall Street, "EPS Accretion/Dilution: Rules of Thumb for Merger Models": https://breakingintowallstreet.com/kb/ma-and-merger-models/eps-accretion-dilution/ (checked June 2026)
- Wall Street Oasis, "Accretion/Dilution Model": https://www.wallstreetoasis.com/resources/financial-modeling/accretion-dilution-model (checked June 2026)