Sell-Side M&A Process: A Step-by-Step Guide for Owners

Selling a business is one of the most consequential financial events of an owner’s life — and one of the least understood. Most owners have built their company over years or decades, but the mechanics of a structured sale process are unfamiliar territory. Investment bankers describe it from the perspective of their role. Buyers describe it from the perspective of their objectives. Very few resources walk you through it from the seller’s chair.

This guide does exactly that. Whether you are actively exploring a sale or simply want to understand what you’re getting into, here is how a sell-side M&A transaction actually works — and where your attorney’s role matters most at each stage.

Stage 1: Pre-Sale Preparation

Before your business goes to market, groundwork determines whether you attract serious buyers and achieve your target price. This phase involves organizing corporate records and financial statements, resolving known legal or structural issues, confirming your management team’s continuity plan, and aligning with your advisors — attorney, accountant, and investment banker — on deal structure and a realistic valuation range. Understanding the core business valuation methods buyers use is essential at this stage.

Sellers who skip this stage tend to discover problems during buyer due diligence. That is the worst possible time to learn about a cap table defect, an unsigned customer contract, or a liability you thought was resolved. Fixing issues before going to market protects your price; fixing them mid-diligence costs you leverage. For a deeper look at the groundwork that pays off, see our guide on preparing to sell your business in four steps.

Stage 2: Signing a Confidentiality Agreement

Before any substantive information about your business is shared with a prospective buyer, both parties execute a non-disclosure agreement (NDA). At this stage, your attorney should review the NDA to confirm that its definitions of confidential information are appropriately broad, that any standstill or non-solicitation provisions are acceptable, and that the agreement reflects your specific situation.

NDAs are frequently treated as form documents. They are not. A poorly drafted NDA can leave your customer lists, pricing data, and key employee information exposed if a deal falls apart.

Stage 3: Indications of Interest

After reviewing your confidential information memorandum (CIM), interested buyers submit non-binding indications of interest (IOIs). An IOI typically includes a proposed price range, a preliminary sense of deal structure — asset versus stock purchase — and any major conditions. IOIs are not binding, but they signal a buyer’s seriousness and frame the negotiation to come. Your advisors evaluate them not just on price, but on deal structure, buyer financing, and realistic probability of closing.

Stage 4: Letter of Intent

The LOI is the most pivotal pre-close document in a sell-side transaction. It is largely non-binding, but it establishes the economic deal points — purchase price, payment structure, earnout mechanics, escrow arrangements — that will govern your negotiating posture in the purchase agreement. Once signed, the LOI typically includes an exclusivity period during which you cannot solicit other buyers.

Many sellers sign LOIs without adequate legal review, only to spend weeks fighting uphill to recover ground in the purchase agreement. The LOI deserves the same attention as the definitive agreement. For a closer look at the terms that matter most, see our breakdown of the most important deal points in a letter of intent. This is where experienced M&A counsel earns the engagement.

Stage 5: Due Diligence

Following LOI execution, buyers conduct comprehensive due diligence. They will review your financial statements (typically three to five years), material contracts, intellectual property, employment records, pending or threatened litigation, regulatory compliance, and real property interests. The process is intensive and typically runs four to ten weeks depending on deal complexity.

Well-prepared sellers move diligence faster and encounter fewer surprises. Working with your attorney before diligence begins to organize a virtual data room, resolve known issues, and prepare responses to predictable buyer questions is time well spent. Our detailed walkthrough of what buyers examine during M&A due diligence covers each category in depth.

Stage 6: Purchase Agreement

The definitive purchase agreement — whether a stock purchase agreement (SPA) or asset purchase agreement (APA) — is the governing deal document. It covers representations and warranties (the factual statements each party makes about the transaction), indemnification provisions (who bears risk for breaches), purchase price adjustments (typically working capital mechanics), and closing conditions. The structural choice between asset purchase versus stock purchase shapes virtually every section of this agreement, which is why it should be locked down in the LOI.

Representation and warranty insurance (RWI) has become increasingly common in mid-market transactions, shifting some post-closing indemnification risk to an insurer rather than leaving it between buyer and seller. Your attorney should advise on whether RWI makes sense for your deal and how it affects the indemnification negotiation.

Stage 7: Closing

Closing involves executing the definitive agreements, wiring the purchase price, transferring ownership, and satisfying all conditions precedent — regulatory approvals, third-party consents, lender payoffs. Your attorney coordinates the closing checklist, manages the flow of funds, and confirms that all deliverables are in order before the transaction is deemed closed.

Post-close, there are often outstanding obligations: earnout periods to manage, working capital true-ups to negotiate, and transition services to provide. The transaction does not end at the wire.

The Role of Counsel Throughout

Experienced M&A counsel is a strategic partner from pre-market preparation through post-close — not just a document reviewer. That means advising on deal structure, evaluating LOI terms with an eye toward the purchase agreement, managing diligence preparation, negotiating representations and indemnification caps, and coordinating closing mechanics. If you are considering a sale of your business, the time to engage counsel is before the LOI, not after.

➤ Contact Petersen | Landis for a confidential consultation with our M&A team.