Accretion/dilution analysis answers one deceptively simple question: after an acquisition closes, does the combined company's earnings per share (EPS) go up (accretive) or down (dilutive) relative to the acquirer's EPS before the deal? It's one of the first tests bankers and corporate development teams run on any deal, and it's a near-certain topic in M&A interviews — precisely because it forces a candidate to connect deal structure, financing choice, and accounting mechanics in one calculation.
Why accretion/dilution matters
EPS accretion or dilution isn't the only thing that determines whether a deal creates value — a dilutive deal can still be strategically sound, and an accretive one can still destroy value if the acquirer overpays for the wrong reasons. But because EPS is so closely watched by public-market investors and analysts, management teams treat the accretion/dilution outcome as a real constraint on what they can announce. A CFO pitching a deal to the board wants to know, before signing anything, whether the market is likely to read the transaction as EPS-accretive or EPS-dilutive on day one.
The core intuition: whose earnings are you buying, and how are you paying for them?
At its simplest, accretion/dilution comes down to comparing two things: the multiple the acquirer is effectively paying for the target's earnings (the transaction P/E), and the multiple the acquirer trades at itself. If the acquirer issues stock — trading at, say, 20x its own earnings — to buy a target's earnings at a 25x transaction multiple, it is "buying expensive earnings with cheap currency," and the deal tends to be dilutive. Buy earnings cheaper than your own trading multiple, and the reverse holds.
Financing with cash instead of stock changes the comparison: instead of weighing P/E multiples, you're comparing the target's earnings yield (net income divided by purchase price) against the after-tax cost of the debt or cash used to fund the deal. If the after-tax cost of financing is higher than the yield the target's earnings generate on the price paid, the cash deal is dilutive too.
Where synergies fit in
Synergies — cost savings or revenue gains expected from combining the two businesses — are usually the lever management points to when a deal looks dilutive on a standalone basis. The relevant question in an interview or a real deal team meeting isn't just "are there synergies," but "how much pre-tax synergy, on a run-rate basis, would it take to make this deal EPS-neutral?" That's a specific, calculable number, and being able to solve for it — rather than gesturing vaguely at "cost synergies" — is what separates a strong interview answer from a weak one.
Building the full analysis
Accretion/Dilution: The Basic Concept introduces the core all-stock version of this question — determining whether a 100% stock deal is accretive or dilutive and why that alone doesn't settle whether the deal makes sense. Full Accretion/Dilution Analysis builds the complete version of the model: pro-forma EPS under both an all-cash and an all-stock structure, side by side, followed by the pre-tax synergy target each structure would need to break even. Working through both cases with real numbers — offer price, purchase price, after-tax interest expense, new shares issued — is the fastest way to internalize the mechanics well enough to reproduce them cold in an interview.
Once you're comfortable with the EPS impact itself, Synergy Valuation goes a step further and asks how you'd risk-adjust and discount those synergies to determine whether the price paid for them is actually justified — a natural follow-up question once you've nailed the accretion/dilution mechanics.