M&A Due Diligence in 2026: What Financial Due Diligence (FDD) Actually Finds

In a deal process, the financial statements are just the starting point. Financial Due Diligence (FDD) is where buyers (and sellers) stress-test the story behind the numbers: what earnings are repeatable, what working capital is really required, and what risks could turn “good EBITDA” into a painful post-close surprise.

This guide explains what FDD covers, how it’s typically run, and the highest-impact items you can prepare before your deal team asks for them.

What Is Financial Due Diligence (FDD)?

FDD is a structured analysis of a company’s historical financial performance, cash flows, and working capital dynamics—usually performed in buy-side diligence, and often mirrored on the sell-side to get ahead of buyer questions.

Most FDD workstreams roll up into three core outputs:

Quality of Earnings (QoE): What EBITDA (or earnings) is sustainable versus one-time, non-operating, or misclassified.
Net Working Capital (NWC): What “normalized” working capital is required to run the business—and how it impacts the purchase price at close.
Cash / Debt-like Items: What affects true cash generation and what should be treated as debt-like (or a purchase price adjustment).

Why FDD Matters (Even If You “Trust the Books”)

Deals don’t fail because the books are off by $12. They fail because expectations break. FDD aligns the buyer and seller on the economics of the business—before money changes hands.

        Common deal-killers (or valuation reducers)
        EBITDA includes one-time revenue or under-accrued expenses
Gross margin shifts that aren’t explained by mix, pricing, or costs
Working capital targets that don’t reflect seasonality or true run-rate needs
Customer concentration risks that aren’t visible in the P&L
“Debt-like” obligations hiding in operating accounts (bonuses, taxes, AR disputes)

    

The 3 FDD Pillars (and What Each One Tests)

1) Quality of Earnings (QoE)

QoE is about sustainable earnings power. The question isn’t “What did EBITDA say?” It’s “What should EBITDA be—on a normal, repeatable basis?”

QoE adjustments buyers often ask about

☐ One-time revenue (large projects, settlements, unusual rebates)
☐ Non-recurring costs (legal events, severance, relocation)
☐ Owner / related-party items (comp, rent, vehicles, travel)
☐ Capitalization policy shifts (capex vs. opex swings)
☐ Accrual quality (bonuses, commissions, PTO, warranties)
☐ Revenue recognition and cutoff consistency
☐ Classification issues (COGS vs. opex, below-the-line items)

2) Net Working Capital (NWC)

NWC is often where “headline price” turns into “actual price.” Most deals use a working capital peg/target. If you deliver less working capital than the target at close, purchase price may be reduced (and vice versa).

NWC topics that create price friction

☐ AR aging quality (disputes, credits, old balances)
☐ Revenue vs. cash timing (DSO trends and seasonality)
☐ Inventory valuation and reserves (slow-moving, obsolete)
☐ AP cutoff and completeness (unrecorded liabilities)
☐ Deferred revenue / customer deposits treatment
☐ “Operating” vs. “non-operating” balance sheet classification

3) Cash, Debt-like Items, and True Free Cash Flow

Even profitable businesses can be cash-poor. FDD helps explain why, and identifies obligations that behave like debt, even if they’re not booked as traditional borrowings.

Debt-like / cash flow watchouts

☐ Unpaid taxes, payroll liabilities, sales tax/VAT exposures
☐ Accrued bonuses/commissions tied to pre-close periods
☐ Customer credits / rebates / returns reserves
☐ Lease-like commitments or off-balance-sheet obligations
☐ Litigation, warranty, or remediation exposures

A Practical 4-Week FDD Prep Timeline (Seller-Friendly)

Week 1: Clean the close and tie-out schedules

Finalize monthly financials (at least 24 months if available)
Ensure balance sheet tie-outs exist for key accounts
Document significant journal entries (what/why/support)

Week 2: Build a QoE-ready P&L bridge

List “non-recurring” items with documentation
Identify owner-related items and normalization logic
Prepare a margin story (price, volume, mix, cost changes)

Week 3: Prepare NWC trend views

AR aging + top customer balances and disputes
Inventory rollforward + reserves rationale
AP aging + subsequent payments view

Week 4: Anticipate diligence questions

Customer concentration, churn, and contract terms summary
Revenue recognition policy summary (plain English)
Debt-like items list and your position on treatment

High-Signal Red Flags Buyers Notice Fast

        Red flags that trigger deeper testing
        “Plug” accounts that move every month (misc income/expense, clearing accounts)
Margin volatility without operational explanation
AR aging drift paired with aggressive revenue growth
Inventory build without clear demand drivers
Cutoff issues (large end-of-month revenue or missing accruals)
Heavy manual JEs without consistent support

    

What to Put in Your “FDD Data Room” (Minimum Viable Set)

If you want diligence to move quickly, start with a clean baseline package. A typical minimum set includes:

Monthly P&L and Balance Sheet (24–36 months if available)
Trial balance detail by month (or at least year-to-date with comparatives)
General ledger detail for major accounts
AR aging + customer list (with terms)
AP aging + vendor list (with terms)
Inventory detail and valuation policy (if applicable)
Revenue by customer / product / service line
Debt schedule, leases, and key contracts
Tax filings and payroll reports (as relevant)

Buy-Side vs. Sell-Side FDD: Which One Do You Need?

Buy-side FDD helps buyers validate the deal thesis and price the risk. Sell-side FDD helps sellers control the narrative and reduce last-minute surprises.

If you’re going to market soon, sell-side FDD often pays for itself by reducing retrades, shortening timelines, and increasing buyer confidence.

Conclusion: FDD Is About Fewer Surprises

The best diligence outcome isn’t “no questions.” It’s clear answers, backed by schedules, consistency, and a coherent story that ties performance to operations.

If you’re preparing for a transaction—or you just want to know how a buyer will view your numbers—start with a QoE bridge, clean NWC support, and a short list of debt-like items. Those three pieces eliminate most friction before it starts.

Want a Deal-Ready FDD Prep Package?

We can help you assemble a buyer-grade QoE + NWC support pack, identify red flags early, and reduce diligence churn. Ideal for owners, finance leaders, and advisors preparing for a sale or capital raise.

Schedule a Consultation