Buy-Side Due Diligence: What It Is, What It Covers, and How to Do It Right

Buy-Side Due Diligence: What It Is, What It Covers, and How to Do It Right

You're under LOI. The seller is cooperative. Your attorney says the purchase agreement looks clean. Your lender says they need 30 more days to finalize the commitment letter. And everyone keeps telling you to "do your due diligence."

But nobody has given you a clear answer on what buy-side due diligence actually means — what gets covered, who does what, and how to know when you've done enough.

This guide covers all of it.

What Buy-Side Due Diligence Actually Is

Buy-side due diligence is the process a buyer uses to verify what they're buying before closing. It's your chance to confirm that the business performs the way the seller says it does — and to find problems before they become your problems.

Due diligence typically happens after you sign an LOI and before you sign the purchase agreement. The seller gives you access to their books, contracts, customer data, employee records, and operational systems. Your job is to go through it all systematically and decide whether the deal still makes sense at the agreed-upon price.

There are several workstreams that run in parallel:

- Financial due diligence — Are the earnings real, recurring, and sustainable? - Legal due diligence — Are there contracts, liabilities, or lawsuits that change the picture? - Operational due diligence — Does the business actually run the way the seller describes? - Tax due diligence — Are there any tax liabilities coming with the business? - Commercial due diligence — Is the market position as strong as the seller says?

For most lower middle market transactions ($1M–$30M), financial due diligence is the most critical workstream. It's where the surprises live, and it's where deals most commonly reprice or fall apart.

Why Financial Due Diligence Is the Heart of the Process

Most small and lower middle market businesses are owner-operated. The seller runs payroll through the company, books personal expenses as business expenses, and keeps their books on a cash basis or somewhere in between. None of this is fraud — it's just how these businesses work.

The problem is that the P&L the seller hands you reflects how the business runs for them, not how it will run for you. Your job — and your QoE provider's job — is to reconstruct the economic reality of the business.

A real example: We were engaged on a $5.2M acquisition of a plumbing services company. The seller's P&L showed $680K in adjusted EBITDA. After normalization, the real number was $490K. The difference came from three places: the seller was paying himself $40K when a replacement operations manager would cost $120K — an $80K hit to run-rate earnings; $70K of "revenue" was a one-time pandemic-era grant the seller had folded into the recurring P&L; and the seller had added back $40K for his spouse's salary, but she ran dispatch and the buyer needed to hire someone to do the same job. The buyer repriced the deal. The seller accepted. The deal closed.

That's what financial due diligence is for.

What a Quality of Earnings Report Covers

For most deals in the $1M–$30M range, financial due diligence means getting a Quality of Earnings report. A QoE is a focused financial analysis that answers one question: are the earnings real?

A complete QoE covers:

Revenue analysis - Revenue recognition policies — is revenue booked when earned or when cash comes in? - Customer concentration — does one customer represent 30%+ of revenue? - Recurring vs. one-time revenue — what percentage of next year's revenue is already contracted? - Seasonality — does the business have a predictable revenue pattern or is it lumpy?

Expense normalization - Owner compensation — what does the seller actually take home, in all its forms? - Add-backs — which expenses are genuinely one-time and which will continue under new ownership? - Related-party transactions — are there vendor or customer relationships that disappear when the seller leaves? - Rent — is the real estate owned by the seller at above- or below-market rates?

Working capital analysis - What level of working capital is needed to run the business day-to-day? - What's the historical working capital pattern? - What's the right working capital peg for the purchase agreement?

Balance sheet review - Are accounts receivable collectible? - Is inventory properly valued? - Are there off-balance-sheet liabilities?

The QoE report does not replace an audit. It's a targeted analysis focused on what matters for the deal, not a comprehensive test of every financial assertion. For more on when an audit is appropriate instead, see our guide on QoE vs. audit.

Who Does What in Buy-Side Due Diligence

Due diligence involves multiple advisors, and it's worth understanding who handles what:

For a typical $5M transaction, you're coordinating 4–6 advisors simultaneously under a tight timeline. The LOI usually gives you 45–90 days to close. Due diligence typically needs to wrap up 2–3 weeks before closing to give attorneys time to finalize documents.

A Practical Due Diligence Timeline

Here's a realistic schedule for a $3M–$10M deal with a 60-day LOI period:

Days 1–7: Setup - Execute NDAs and access agreements - Request initial document list from seller - Engage QoE provider, attorney, tax advisor - Set up virtual data room

Days 8–21: Document collection and initial review - QoE provider reviews financial statements, tax returns, and bank statements - Attorney begins contract and liability review - Initial management call with seller

Days 22–35: Deep dive - QoE provider conducts detailed analysis, requests follow-up items - Management meeting / site visit - Tax advisor begins review of returns and structure

Days 36–45: Draft deliverables - QoE draft report delivered for buyer review - Attorney delivers issues memo - Buyer reviews findings and assesses impact on deal terms

Days 46–55: Negotiation and finalization - Renegotiation if QoE findings support price adjustment - Purchase agreement markup - Final financing terms from lender

Days 56–60: Closing prep - Final versions of all documents - Wire instructions confirmed - Working capital target set based on QoE findings

If you're using SBA financing, add another 2–3 weeks for SBA underwriting. SBA lenders move at their own pace and the commitment letter is not something you can rush.

The Most Common Mistakes Buyers Make

Starting too late. Some buyers wait until they have the purchase agreement drafted to engage due diligence advisors. By then, you've lost 2–3 weeks and are racing to close on the seller's timeline. Engage your QoE provider the same week you sign the LOI.

Assuming the broker's add-backs are real. Every seller's package includes a list of adjustments to EBITDA. Some of those adjustments are legitimate. Some are not. The broker's job is to maximize the asking price, not to vet every line item. Your QoE provider's job is to scrutinize them.

Not getting enough bank statements. Bank statements are the ground truth of any business. They show every deposit and payment, and they don't lie. If a seller won't provide full bank statements for 24–36 months, that's a red flag.

Skipping the management call. The financial analysis will tell you what the numbers say. The management call will tell you why. Get a structured conversation with the seller on record before you close.

Ignoring customer concentration. A business that does 40% of its revenue with one customer is a fundamentally different business than one with diversified revenue. One call ends the relationship, and the business is worth half what you paid. The QoE will flag it — make sure you're paying attention.

What to Do With What You Find

Due diligence findings fall into three categories:

1. Deal-killers — Issues that make the business un-buyable at any price. Key-person risk with no transition plan, unresolved environmental liability, revenue that isn't real.

2. Price adjustments — Real EBITDA is lower than represented, which justifies a lower purchase price. This is the most common outcome. Most deals reprice by 5–20% after diligence.

3. Post-close protections — Issues you can live with but want covered: indemnification provisions, escrow holdbacks, earnouts tied to seller performance.

A good QoE report doesn't just tell you what the earnings are — it tells you what to negotiate.

Getting Started

If you're under LOI or approaching the LOI stage, the time to engage a QoE provider is now — not after you've signed the purchase agreement. The QoE drives the working capital peg, informs the reps and warranties, and gives your lender the financial confidence they need to fund the deal.

Bedrock runs buy-side QoE engagements for deals in the $1M–$40M range. We turn around reports in 2–4 weeks. If you want to talk through what your deal needs, reach out here.