The due diligence playbook for middle market transactions has evolved significantly. While financial, legal, and operational assessments remain foundational, a new category has emerged as essential: marketing due diligence. Sophisticated investors and lenders now recognize that understanding how a company acquires and retains customers provides critical insight into revenue quality, scalability, and ultimate business sustainability.
A 2023 Bain & Company study found that commercial excellence initiatives focused on sales and marketing were the top driver of revenue growth for private equity portfolio companies, delivering an average revenue uplift of 27%.¹ Yet fewer than 25% of PE firms have a digital diligence module integrated into standard operating models, according to Bain, despite digital channels accounting for over 50% of marketing spend across industries.²
The Core Metrics: CAC, LTV, and the Economics of Growth
At the heart of marketing due diligence lies a fundamental question: Can this company acquire customers profitably and sustainably? The answer emerges from rigorous examination of customer acquisition cost (CAC) relative to lifetime value (LTV).
Customer Acquisition Cost (CAC): A comprehensive CAC calculation includes all costs associated with acquiring customers—media spend, creative development, personnel costs, and technology expenses. “Calculate CAC comprehensively, crunching all the numbers for media, creative, as well as personnel costs,” advises fusepoint in their PE diligence framework.³ Incomplete CAC calculations can mask unsustainable economics that only become apparent post-acquisition.
LTV/CAC Ratio: The relationship between lifetime value and acquisition cost reveals business model health. “A healthy ratio (typically 3:1 or higher) indicates that the company generates more revenue from each customer than it spends to acquire them, ensuring long-term profitability,” notes industry guidance.⁴ Ratios below this threshold raise questions about scalability and margin sustainability.
Payback Period: Ideally, companies should recoup their CAC within twelve months to maintain sustainable growth. “Anything greater than two years is a red flag,” cautions the Seraf investor framework.⁵ Extended payback periods strain working capital and increase vulnerability to competitive or market disruptions.
Red Flags and Warning Signs
Sophisticated diligence goes beyond headline metrics to identify potential problems hidden in the details. “If numbers show that CAC has been accelerating while LTV stays static, it signals that a deal may be resting on unrealistic or deceptive scaling assumptions,” warns fusepoint’s analysis.⁶
Channel Concentration Risk: Many brands lean heavily on one or two platforms, compromising total portfolio health. A company generating 80% of customers through a single paid social channel faces significant risk if that channel’s economics deteriorate or if algorithm changes reduce effectiveness.
Attribution Accuracy: “One of the most overlooked diligence questions is: ‘Do reported results reflect real, measurable incremental growth?'” Companies often report ROAS or attribution metrics that exaggerate marketing’s impact.⁷ Investors must distinguish between marketing that genuinely drives incremental revenue versus activities that merely correlate with organic demand.
Retention Sustainability: High churn rates compound CAC problems. “If it appears older customers are churning at a higher rate than new customers are being acquired, this may be a sign that the product isn’t sticky or has significant issues.”⁸ Net and gross dollar retention metrics reveal whether companies extract full value from customer relationships.
Ecosystem Implications
For Private Equity Sponsors: Marketing due diligence informs both entry valuation and value creation planning. Understanding customer acquisition economics at acquisition enables realistic projections and identifies specific improvement opportunities. PE operating partners increasingly need marketing expertise to evaluate portfolio company performance and guide post-acquisition optimization.
For Lenders: Customer acquisition sustainability directly impacts credit quality. A company with deteriorating CAC economics or excessive channel concentration presents higher risk than traditional financial metrics might suggest. Lenders should incorporate marketing health indicators into ongoing portfolio monitoring, not just initial underwriting.
For Investment Bankers: Preparing clients for marketing diligence has become essential for successful processes. Companies that can present clear, auditable customer acquisition metrics command premium valuations. Bankers should help portfolio companies organize marketing data and articulate growth strategies before going to market.
For Legal Advisors: Data privacy compliance and customer data ownership have become critical diligence areas. Legal teams should ensure marketing practices comply with evolving privacy regulations and that customer data assets are properly protected and transferable.
For Turnaround Advisors: Distressed companies often exhibit marketing dysfunction—unsustainable CAC, deteriorating retention, or channel dependency—before financial distress becomes acute. Early identification of marketing problems can enable intervention before situations become critical.
The Path Forward
Marketing due diligence has evolved from a nice-to-have into a deal requirement. “Metrics such as CAC, CLTV and NRR are non-negotiable,” states VCMO’s private equity diligence framework. “They reveal the quality and economics of growth, helping investors distinguish between sustainable customer value and revenue patterns driven by discounting, concentration or one-off events.”⁹
As the middle market dealmaking ecosystem continues to mature, participants who develop sophisticated understanding of customer acquisition economics will identify better opportunities and avoid costly mistakes. The companies that can clearly demonstrate sustainable, scalable growth engines will command premium valuations—and the investors who can accurately assess those engines will generate superior returns.
Sources
¹ Magnus Consulting, “The Critical Role of Sales and Marketing Due Diligence in Private Equity Investments,” October 2025: https://magnusconsulting.co.uk/sales-and-marketing-due-diligence/
² Claymore Partners, “Marketing As An Asset Class,” 2025: https://www.claymorepartners.com/due-dilligence-checklist
³ fusepoint, “Marketing Due Diligence Checklist for PE & Corporate Buyers,” November 2025: https://fusepointinsights.com/blog/marketing-due-diligence-checklist/
⁴ Boomn, “The Ultimate Guide to Marketing Due Diligence for Private Equity Firms”: https://www.boomn.com/blog/the-ultimate-guide-to-marketing-due-diligence-for-private-equity-firms
⁵ Seraf Investor Portal, “Due Diligence: Evaluating Go-To-Market Strategy”: https://app.seraf.io/compass/article/what-market-will-bear-evaluating-go-market-strategies
⁶ fusepoint, “Marketing Due Diligence Checklist,” November 2025: https://fusepointinsights.com/blog/marketing-due-diligence-checklist/
⁷ fusepoint, “Marketing Due Diligence Checklist,” November 2025: https://fusepointinsights.com/blog/marketing-due-diligence-checklist/
⁸ howtosaas, “The Ultimate Marketing Due Diligence Checklist”: https://www.howtosaas.com/blog/due-diligence-checklist-for-acquisitions
⁹ VCMO, “Marketing Due Diligence in Private Equity: The Complete Guide,” 2025: https://www.vcmo.uk/resource/marketing-due-diligence-in-private-equity-a-complete-guide
