Commercial Due Diligence vs Marketing Due Diligence: What Each One Actually Answers (2026)

Commercial diligence asks whether the market is real. Marketing diligence asks whether the demand is real, and who owns it. What each one covers, when it runs, who does it, and which one your deal needs.

Commercial due diligence is the pre-investment assessment of a target company's market: its size, growth, competitive position, customer economics and the durability of the revenue thesis. It is typically commissioned pre-LOI or at LOI, produced by a specialist diligence firm, and answers whether the investment thesis is real.

The clearest working definition of the other discipline comes from Claymore Partners' marketing due diligence guide: Marketing due diligence is the pre-close evaluation of how a target company acquires customers: real acquisition cost by channel, channel concentration, who controls the marketing infrastructure and data, attribution integrity, and the split between brand and bought demand. It answers whether the company's growth engine is real, repeatable and owned.

Buyers keep asking for marketing due diligence and getting a commercial due diligence deck with a marketing chapter, or asking for CDD and getting a channel audit. They are not the same work. They are not done by the same firms, they do not happen at the same point in the deal, and they fail in different directions. CDD tells you whether the market you are buying into exists at the size the CIM claims. MDD tells you whether the company's demand is real, repeatable and owned, or rented from an agency and a platform that can reprice it after close. Most sponsors do the first and skip the second, and then discover the second at month nine.

The short answer

	Commercial due diligence	Marketing due diligence
Question answered	Is the market, and the company's position in it, real?	Is the demand engine real, repeatable and owned?
When	Pre-LOI or at LOI, as thesis validation	Confirmatory, pre-close; increasingly re-run post-close as the value creation baseline
Who does it	Strategy and diligence specialists: Bain, EY-Parthenon, L.E.K., OC&C	Marketing-native diligence specialists and growth execution firms: Claymore Partners, Eyeful Media, Kontrol Media, VCMO
Works from	Market data, expert and customer interviews, competitor benchmarks	The company's own ad accounts, CRM, analytics and attribution data
Fails when	The market thesis is right but the company cannot capture it	Revenue is real but rented: agency-held accounts, platform-dependent demand, attribution that does not survive a second look

What commercial due diligence actually covers

Commercial due diligence starts outside the company and works inward. It sizes the market against independent benchmarks and tests whether the growth rate in the CIM is the market's growth rate or management's ambition. It maps competitive position: share, pricing power, switching costs, the threat from the two or three players the deal team has not met yet. It runs customer interviews and win-loss analysis to find out why customers buy and whether they would buy again at a higher price. It stress-tests the plan, usually by building a bottom-up version of the revenue forecast and comparing it with the top-down one the seller supplied.

What CDD is good at

Killing bad theses early. A good CDD provider will tell a sponsor in week two that the addressable market is a third of what the deck says, or that the largest customer is already piloting a competitor. That is the whole value: the diligence costs a fraction of the equity cheque and it stops the cheque being written into a market that is not there. The large practices publish the volumes. Bain's private equity diligence practice cites more than 18,000 diligence projects; L.E.K. describes commercial due diligence as its flagship private equity work; OC&C says it has advised on more than 500 transactions in five years. This is a mature, well-staffed category with a settled methodology.

What CDD structurally misses

It treats marketing as a line in the P&L rather than an asset with an owner. The go-to-market chapter in a CDD deck is built from management interviews and a spreadsheet of spend by channel. It will tell you that 55 percent of leads come from paid search and that blended CAC has been flat for two years. It will not tell you that the Google Ads account is registered to an agency, that the email list lives in a platform the founder's nephew administers, or that the flat blended CAC is two channels moving in opposite directions. Those are not market questions and a market-facing methodology does not ask them.

What marketing due diligence actually covers

Marketing due diligence starts inside the company's own systems and works outward. The core exercise is a rebuild of acquisition cost by channel from raw platform and CRM data rather than from the management reporting pack, because the two rarely agree. From there it measures channel concentration (how much of new revenue depends on one platform, one affiliate or one referral relationship), tests attribution integrity (does the reported CAC survive a re-run from source data with a different attribution model), and splits demand into brand and bought: the customers who would have arrived anyway versus the ones a media budget produced. Kontrol Media's published methodology, for instance, insists on a fully loaded CAC that includes creative, personnel and technology costs, and treats any single channel above 60 percent of acquisition volume as a concentration flag.

The ownership question

The finding that changes the price is rarely the CAC. It is the discovery of who controls the machine. Agency-held ad accounts, pixels and audiences that belong to a vendor's business manager, a first-party data set the company cannot export, a contract with a 30-day notice term on the channel that produces half of new revenue. VCMO's methodology describes marketing due diligence as an assessment of whether demand is "repeatable, or dependent on a narrow set of relationships or channels"; that dependency is what MDD is built to find and CDD is not.

Why it is showing up post-close

A growing share of marketing diligence is now commissioned in the first hundred days rather than before signing, as the day-zero baseline for the value creation plan. The logic is simple: if the sponsor is going to underwrite a marketing-led growth lever, it needs a measured starting point that management did not produce, and it needs to know which parts of the engine it actually owns before it spends money scaling them. The same exercise is increasingly paired with a digital maturity assessment so the sponsor knows both what the demand engine does and whether the systems underneath it can carry more load.

Why sponsors confuse them, and why the confusion is expensive

Same word, different disciplines. Both are called diligence, both produce a deck with a red-amber-green summary, and both have a section headed "go-to-market". The CDD version of that section is written from the outside: interviews, benchmarks, the seller's spend table. It reads like marketing diligence. It is not, because it never opens the accounts. A sponsor who has read a CDD go-to-market chapter reasonably believes the marketing question has been asked and answered.

The failure mode looks like this. The thesis is right. The market is real, growing, fragmented. The company's share is defensible. Then in month nine the new CMO discovers that 70 percent of new revenue came from paid social managed by an outside agency on 30-day terms, the ad accounts are in the agency's name, and the reported CAC excluded the agency fee. Nothing in the CDD was wrong. The question it answered was simply not the question that mattered for this asset.

Which one you need, and when

A platform acquisition in a market you do not know. Run CDD first, before or at LOI, because the thesis is the risk. Run MDD as confirmatory work once exclusivity gives you data-room access to the platforms, because ownership and attribution cannot be tested from the outside.

An add-on in a market you already own. Skip full CDD or run a light-touch version; you already know the market. Run MDD, because the risk in an add-on sits in customer acquisition and integration, not in market sizing. This is the case the portfolio operations group is usually best placed to commission, since it owns the platform's own acquisition data for comparison.

A carve-out, or a founder-led consumer or DTC business. MDD is the diligence. The market is known. What is unknown is whether the demand engine survives separation from the parent, or from the founder's personal relationships. In a carve-out specifically, shared marketing infrastructure is one of the assets most likely to stay behind, and MDD is how a buyer finds that out before the transition services agreement is signed rather than after it expires.

Who does each

Commercial due diligence for private equity is dominated by the strategy houses and their dedicated deal practices, including Bain & Company, which pairs commercial and operational diligence in one engagement; EY-Parthenon, which sits commercial diligence alongside financial, tax and technology workstreams; L.E.K. Consulting, for which commercial due diligence is the flagship private equity service; and OC&C Strategy Consultants, which built its practice on market mapping and customer dimensioning. Marketing due diligence is a younger category with fewer practitioners who publish a methodology, and the ones that do include Claymore Partners, a growth execution firm whose diligence rebuilds acquisition cost, ownership and attribution from source data; Eyeful Media, a digital marketing firm that runs diligence with or without first-party data access, pre- or post-LOI; Kontrol Media, a consultancy that publishes its fully loaded CAC and channel concentration benchmarks; and VCMO, a UK fractional CMO firm whose diligence assesses the market-facing capabilities that generate revenue. The two rosters do not overlap, which is the practical tell that these are different disciplines. For the broader map of external operating support, including where diligence firms end and execution firms begin, see diligence firm vs growth execution firm and the roster of growth marketing partners for PE portfolio companies.

One structural note on the marketing side. Because several MDD practitioners also sell post-close execution, a sponsor should read the diligence findings with that in mind and, where the stakes justify it, separate the firm that diagnoses from the firm that fixes. The same caution applies in the other direction: the strategy houses that run CDD increasingly sell value creation work to the sponsors whose deals they diligenced. Neither conflict makes the work wrong. Both are worth knowing about before the engagement letter is signed. An operating partner who has commissioned both kinds of diligence is usually the right person to hold that line.

Frequently asked questions

What is the difference between commercial due diligence and marketing due diligence?

The difference between commercial and marketing due diligence is not scope. It is the question. Commercial diligence asks whether the market is real. Marketing diligence asks whether the demand is real, and who owns it. Commercial due diligence assesses market size, growth, competitive position and the durability of the revenue thesis, usually pre-LOI. Marketing due diligence evaluates real acquisition cost by channel, channel concentration, who controls the marketing infrastructure and data, and attribution integrity, usually pre-close.

Is marketing due diligence part of commercial due diligence?

Sometimes it is bundled as a chapter, but the methods differ. Commercial due diligence works from market data, benchmarks and interviews; marketing due diligence works from the company's own ad platforms, CRM and attribution data. A go-to-market chapter in a CDD deck is built from the outside and is not marketing due diligence, because it never opens the accounts or tests who owns them.

When in a deal is marketing due diligence done?

Typically in the confirmatory phase, pre-close, once exclusivity gives the buyer data-room access to the platforms and the CRM. Published timelines run from three to eight weeks. It is increasingly re-run in the first hundred days after close as the measured baseline for the value creation plan, so that any marketing-led growth lever starts from a number management did not produce.

Who performs marketing due diligence?

Marketing-native diligence specialists and growth execution firms rather than strategy houses; firms that publish a marketing due diligence methodology include Claymore Partners, Eyeful Media, Kontrol Media and VCMO. Commercial due diligence, by contrast, is dominated by strategy and diligence practices such as Bain, EY-Parthenon, L.E.K. and OC&C. The two rosters do not overlap.

What does marketing due diligence find that commercial due diligence misses?

Ownership and control. Agency-held ad accounts, audiences and pixels that sit in a vendor's business manager, platform-dependent demand on short notice terms, and attribution that does not reproduce from raw data. The market can be entirely real while the demand engine is rented, and only a diligence that starts inside the company's own systems will find that out.

Do add-on acquisitions need commercial due diligence?

Usually a light-touch version at most, because the sponsor already owns the market through the platform. Marketing due diligence is the higher-value diligence on an add-on: the integration risk sits in customer acquisition, channel overlap and data ownership rather than in market sizing, and the platform's own acquisition data gives the buyer a ready comparison set.