Small M&A Financial Due Diligence: The Complete Guide — Six Numbers to Check Before Buying a Company

#The Question This Article Answers

In a small-cap M&A deal — buying a company or business priced in the range of a few million to tens of millions of yen — what should the buyer's financial due diligence (financial DD) cover, in what order, and at what cost? This page gives you the full picture.

The short answers first:

• The purpose of financial DD is to turn the numbers in the financial statements into numbers you can actually base a purchase price on. It is neither an audit nor a fault-finding exercise
• In small M&A, a full DD by an accountant (market rate: ¥500K–1M per deal) often doesn't match the deal size. The practical answer is for buyers to run the first screening themselves
• The numbers to check come down to six: normalized EBITDA, net interest-bearing debt, CCC (cash conversion cycle), current ratio, equity ratio, and operating margin
• Risks found in DD are not reasons to walk away — they are material to convert into price and contract terms

I have sold businesses (EXIT) three times, sitting on the seller's side of due diligence each time. I later built DD Tool, a financial DD tool for small M&A. This article is not a textbook summary — it comes from having sat on both sides of the table.

#What Is Financial DD — and How It Differs from an Audit

Financial DD means examining the target's financial statements, tax returns, and books to grasp the company's true earning power and hidden liabilities in a form you can reflect in the purchase price.

It is often confused with an audit, but the goal differs. An audit verifies that statements follow accounting standards; financial DD builds the basis for "how much should I pay, given these statements?" So financial DD re-adjusts everything that distorts economic reality for the buyer — even items that are perfectly legal accounting, such as director compensation inflated for tax purposes.

M&A due diligence also includes legal DD (contracts, licenses, litigation) and business DD (market, competition, customer concentration), but in small M&A, finance comes first: it sets the foundation of price negotiation.

#Small M&A Has a Structural Gap in DD

In listed-company M&A, financial advisers and accounting firms run full DD. The problem is small deals in the millions-to-tens-of-millions range.

A full financial DD from an accountant runs ¥500K–1M per deal. Paying ¥1M of DD cost on a ¥5M acquisition is hard to justify. Yet skipping DD entirely is like buying a used house without a viewing.

When I researched the market before building DD Tool, there was practically no self-service option for financial DD at this price range. Buyers either hunted for individual experts on skill marketplaces, built their own Excel analysis, or gave up and proceeded after "having a look at the statements." Succession-driven listings now fill matching platforms like TRANBI and Batonz, but the asymmetry remains: you can find deals, yet DD stays your own problem.

The realistic fix for this gap is for buyers to own the first-pass screening skill. You don't need to match a professional across the board. If you know which numbers reveal where the landmines are, you can narrow what to outsource — or decide you don't need to.

#The Six Metrics of Financial DD

When I designed DD Tool's analysis engine, I narrowed the metrics for small M&A financial DD down to six. The selection criterion: does it directly affect the purchase price or post-deal cash flow?

#1. Normalized EBITDA — the True Earning Power

EBITDA is the most common proxy for earning power in M&A pricing. But with small-company statements, never use the P&L profit as-is.

Small-company books are usually arranged around tax minimization: generous director compensation, insurance products that compress profit, private expenses mixed into the books. None of this is rare. Reported operating profit therefore looks smaller (or, depending on the owner's intent, larger) than reality.

Normalization removes these distortions: reset director pay to what you'd pay a successor, strip one-off items (subsidies, asset sale gains, pandemic effects), add back private expenses. The adjusted EBITDA is the number you can use in multiple-based pricing.

#2. Net Interest-Bearing Debt — the Bridge from EV to Equity Value

Net debt is interest-bearing debt minus cash. In price negotiation it works through the relation: enterprise value minus net debt equals equity value.

In small deals, director loans (money the owner has lent to the company) often sit in the middle, and how they are treated — waived, converted to equity, or assumed by the buyer — directly moves the price. Always check the breakdown of borrowings.

#3. CCC — Spotting Profitable Companies That Still Run Out of Cash

The cash conversion cycle measures the days from paying suppliers to collecting sales, computed from receivable days, inventory days, and payable days.

A company can show accounting profit and still force you to inject working capital right after closing if its CCC is long. This metric exists to avoid "I could afford the price, then the cash flow killed me" — and it feeds your estimate of required working capital after handover.

#4. Current Ratio — Short-Term Solvency

Current assets over current liabilities: how much of the next year's payments can be covered by assets convertible to cash within a year. Textbooks call 200% ideal and below 100% a warning, but levels vary hugely by industry — read it together with benchmarks, below.

#5. Equity Ratio — Financial Stamina

Equity as a share of total assets. The lower it is, the more the company leans on debt and the less it can absorb rate rises or revenue dips. Insolvent-balance-sheet targets (negative equity) circulate routinely in the small M&A market. Negative equity doesn't mean automatic pass — but it does mean a near-zero price and a credible turnaround story are both required.

#6. Operating Margin — Competitiveness of the Core Business

Operating profit over revenue. On its own it says little; compared against industry peers it tells you whether the company is strong or weak within its sector. Compare using post-normalization numbers.

#Verify Numbers Against Primary Sources

Before computing any metric comes a prior question: can you trust the numbers you were handed? In my own analysis of listed companies I go back to primary filings (EDINET document IDs); with a private small-M&A target, the verification tools change:

• Reconcile the financial statements against the corporate tax return schedules. Double bookkeeping — one set for the bank, one for the tax office — surfaces here
• Confirm cash balances against bank books and balance certificates
• Tie receivables to invoices and payment history of major customers
• Confirm borrowings against repayment schedules and lender balance certificates

Even without seller malice, sloppy bookkeeping is everyday reality in small deals. The rule: never feed handed-over numbers straight into metric calculations.

#Benchmarks Turn Numbers into Judgments

Is a 30% equity ratio good or bad? It depends on the industry — construction and restaurants have completely different standard balance-sheet structures.

I built three industry benchmark sets into DD Tool (METI Local Benchmark, MOF corporate statistics, and TKC BAST — data on 260,000 profitable companies) precisely because standalone numbers cannot be judged. If you work manually, these statistics are public: line up the six metrics against the median for the target's industry.

One more practical point: fix your judgment thresholds before you look at the numbers. DD Tool assigns each metric a mechanical five-level RAG (Red-to-Green) rating partly to block the human bias of bending standards after seeing the target's numbers. The more you want the deal, the kinder you become to the data.

#How to Run Financial DD — Five Steps

1. Request documents. Minimum: three years of financial statements (with account breakdowns), three years of tax returns, latest trial balance, loan repayment schedules, monthly revenue history. Ideally: major customer list, director compensation details, insurance surrender values
2. Verify. Run the reconciliations above; mismatches become your question list for the seller
3. Compute and judge the six metrics. Normalize first, decide thresholds before computing
4. Compare against industry benchmarks. Metrics that deviate far from the industry median are the points to dig into
5. Convert into price and contract terms. See the next section

Steps 1–4 are the "first screening," and buyers can do all of it themselves. When red flags cluster in step 4, or tax and off-balance issues emerge, bring in a professional on those narrowed points — that's where the fee earns itself.

#Convert Found Risks into Price and Contract Terms

DD's output is not a binary buy/no-buy. Most discovered risks convert into negotiation material:

• Residual uncertainty in earning power → an earnout clause: defer part of the price, contingent on post-closing performance. If the seller's claimed earnings are real, they get full price; if not, it self-corrects. Information asymmetry gets priced instead of argued
• Suspected off-balance or contingent liabilities → representations and warranties with indemnification: the seller contractually commits that the statements are true
• Working capital and net-debt drift → a price adjustment clause trued up at the closing date

Speaking from three rounds on the sell side: honest sellers accept this kind of structuring. A seller who refuses earnouts and warranties outright is, in itself, one of the most useful data points DD can produce.

#Financial DD Seen from the Seller's Side

Having supplied documents to buyers' DD three times, here is what that side teaches, translated for buyers.

Document requests are far heavier for the seller than buyers imagine. Some materials always come late. Don't get irritated — observe which documents come late. What arrives instantly is what's routinely managed; what lags is where management is weak. The state of internal controls, which never shows in the metrics, shows in how the documents arrive.

Also: sellers answer what they are asked and rarely volunteer more. Not out of malice — they simply cannot judge what matters to you. Treat the completeness of the question list as the buyer's responsibility.

#The Cost Reality — Outsource, DIY, or Tooling

	Full accountant DD	DIY Excel analysis	DD Tool (mine)
Cost	¥500K–1M per deal	Free (heavy time cost)	Free to start
Coverage	Deep, incl. tax and off-balance	Varies with your design	Focused: 6 metrics + RAG
Industry comparison	Yes	Pull statistics yourself	3 benchmark sets built in
Best for	Larger, complex deals	Accounting-literate buyers	First screening, comparing deals

My recommended order is screen → shortlist → outsource. Run the first screening on every candidate, and only for survivors, hire professionals on the specific red-flagged points. Whether a deal deserves full-DD money is itself a first-screening decision.

I built DD Tool to automate that first screening: enter the financial statement figures and it computes the six metrics including normalized EBITDA, assigns five-level RAG ratings, and compares against industry benchmarks. It runs entirely in your browser and your financial data never leaves your machine (designed to be safe even for NDA-covered material). The analysis is rule-based and deterministic — same input, same result, every time. Try the free version in your browser →

#Summary

• Small M&A financial DD carries a structural gap: accountant full-DD rates (¥500K–1M) versus deal sizes. The realistic answer is buyer-run first screening
• Six numbers to watch: normalized EBITDA, net debt, CCC, current ratio, equity ratio, operating margin
• Verify before computing, set thresholds before judging, and compare against benchmarks rather than reading numbers alone
• Convert found risks into price and contract terms: earnouts, reps and warranties, price adjustments

This pillar article is the hub. Spoke articles answering individual questions — a quick DD checklist, how profit adjustments hide in small-company statements, how DD scope changes between share deals and asset deals — will follow.