M&A Closing Checklist for SaaS Deals: 2026 Guide

An M&A closing checklist for a small SaaS deal has three jobs: collect the signed documents, move the money through escrow, and hand over every technical keys-to-the-kingdom item (code, hosting, billing, domains). Law firm checklists cover the first job well. They say almost nothing about the third, which is where most micro-SaaS closings stall. This guide covers all three, in the order they happen, for founders selling an AI SaaS business and for the people buying one.

TL;DR

• Closing is a sequence, not a day: signed purchase agreement, conditions satisfied, funds in escrow, assets transferred, funds released.
• Most micro-SaaS and AI wrapper deals fall far below the $133.9 million HSR size-of-transaction threshold, but you should confirm that in writing.
• The deal is not done when the wire lands. It is done when repositories, hosting admin, billing and domains are under the buyer’s control.
• Talk to a CPA about transaction-cost treatment before you sign the definitive agreement, not after.
• On AIExchange.club, listing is free, the success fee is a flat 10% with no monthly fees, and every deal closes through escrow with standardized contracts. The marketplace is for AI SaaS businesses.

What closing actually means in a small SaaS deal

In a large private M&A transaction, the closing checklist identifies the parties and the documents each must produce at closing, such as corporate resolutions. That structure still applies to a $40,000 AI tool. What changes is the weight of each item.

A micro-SaaS usually has one owner, no board, no bank debt and no employees on payroll beyond a contractor or two. So the entity-approval section shrinks to a single consent. The technical section grows, because the asset being bought is mostly code, accounts and recurring revenue that sit in a dozen third-party dashboards.

Two terms get confused, so separate them early:

• Signing is when both sides execute the purchase agreement.
• Closing is when the conditions in that agreement are met and ownership actually transfers.

In small deals the two often happen close together, but treating them as separate checklist phases keeps you from skipping a step because the paperwork “feels done.”

The checklist at a glance

These six phases mirror the pipeline we run on AIExchange.club: kickoff call, LOI, due diligence, APA or ATA, escrow, closing. For the full walk-through from first call to close, see our guide to business acquisition steps.

Phase 1: Before you sign anything

Settle the structure

Decide whether this is an asset sale or a stock (entity) sale. It changes liability, tax and which documents you need. Asset deals let the buyer pick what comes across and leave old liabilities behind. Stock deals move the whole entity, contracts and history included. We break down the tradeoffs with a SaaS example in asset sale vs stock sale.

Put confidentiality in place

A seller should not hand over customer lists, MRR screenshots or source code before an NDA is signed. Buyers should expect it. On our platform, listings are protected by NDA, so confidential details stay confidential until a serious buyer is engaged.

Agree on a valuation range

Price disputes kill more deals at the LOI stage than anything else. Sellers can get a data-backed estimate with our AI SaaS valuation quiz, and our AI company valuation guide explains what small AI businesses tend to sell for.

Phase 2: Letter of intent

The LOI is mostly non-binding, with a few exceptions (typically exclusivity and confidentiality). Check that it states:

1. Purchase price and currency.
2. Payment structure: all cash at close, or cash plus a holdback, seller note or earn-out.
3. What is included: code, domains, brand, customer data, social accounts, third-party licenses, support inboxes.
4. Transition period: how many hours or weeks the seller will help, and what that costs, if anything.
5. Exclusivity window for diligence.
6. Any non-compete or non-solicit terms.

If the buyer is financing the purchase, align the funding timeline with the diligence window now. Our piece on how to finance a SaaS acquisition shows the real numbers behind seller notes and lender timing.

Phase 3: Due diligence items that feed the closing

Diligence is its own checklist, and we have one: due diligence checklist for buying a business. For closing purposes, make sure these outputs exist before the definitive agreement is drafted:

• Revenue verification. Payment processor data (Stripe, Paddle, Lemon Squeezy) reconciled against the figures in the listing. Gaps between claimed and actual MRR should be explained in writing, not by a verbal “that was a refund month.”
• Code review. Repository access, dependency audit, and a list of every third-party API the product relies on. For AI products, include model providers, API keys, usage tiers and any prompt or fine-tuning assets.
• Contracts and terms. Customer terms of service, privacy policy, vendor agreements, and any data processing terms.
• Liabilities. Open refunds, chargebacks, unpaid vendor invoices, unresolved support issues.
• IP ownership. Confirm the seller owns the code. Contractor-written code without a signed assignment is a classic closing problem.

On AIExchange.club, revenue and code quality verification are part of how listings are vetted, but buyers should still run diligence against their own priorities.

Phase 4: The definitive agreement

The purchase agreement (an APA for assets, an equity purchase or stock agreement for an entity) turns the LOI into binding terms. A closing checklist at this stage lists each document and who signs it. For a typical small AI SaaS deal, expect:

• Purchase agreement with representations and warranties.
• Disclosure schedules listing exceptions to those representations.
• Bill of sale and assignment of IP (asset deals).
• Seller consent or resolution authorizing the sale. Larger-deal checklists call for corporate resolutions from each party, and a sole-owner version is one short signed consent.
• Domain and trademark assignment.
• Transition services terms, if any.
• Non-compete and confidentiality agreements.
• Escrow instructions.

Our standardized contracts are generated and signed in-platform through DocuSeal, so both sides work from the same templates instead of negotiating a bespoke draft for every deal. That is a large part of why we target closings in under 14 days. It is a target, not a guarantee, and a messy diligence process will stretch it.

Phase 5: Escrow and funding

Transaction escrow is the mechanism that protects both sides while assets move. The buyer deposits funds with a neutral third party, the seller transfers the assets, the buyer confirms receipt, and the funds are released. Neither side has to trust the other with money or code first.

On AIExchange.club, funds are held by Escrow.com, and every deal closes through escrow with standardized contracts.

Things to confirm before the wire:

• The legal names on the escrow account match the names on the purchase agreement.
• Fee allocation is written down: who pays the escrow fee.
• The release conditions match the handover list below, not just “buyer is satisfied.”
• Any holdback or earn-out portion is excluded from the initial release and has its own schedule.

Do not confuse transaction escrow with software escrow

They solve different problems. Transaction escrow holds money. Software escrow is a risk-mitigation tool that helps a buyer gain full technical control of the product. In a straight sale of a small SaaS, a code handover checked during the closing window usually does the job, and a separate software escrow arrangement is more relevant when a vendor keeps running the software for customers over time. Ask your attorney which applies.

Phase 6: The technical handover checklist

This is the section law firm templates leave out. The practitioner view is that a deal is not closed just because the funds are wired. It closes when repositories are transferred, hosting admin credentials are rotated and infrastructure access is fully migrated to the buyer. Missing these steps can delay or derail the deal even after signing.

Use this list, adapted to your stack, and attach it to the purchase agreement as a closing deliverable.

Code and infrastructure

• Buyer added as owner (not collaborator) on every GitHub, GitLab or Bitbucket repository, including archived ones.
• Hosting and cloud accounts (AWS, Vercel, Render, Fly, Supabase, Firebase) transferred or re-created under the buyer’s organization.
• Database backups taken, restored in a test environment and verified.
• CI/CD secrets, environment variables and deploy keys regenerated.
• DNS provider and registrar access moved; domain unlocked and transferred.

AI-specific items

• Model provider accounts (OpenAI, Anthropic, Google and others) either transferred where the provider’s terms allow it, or replaced by buyer-owned accounts with new API keys.
• Old API keys revoked after the new ones are live.
• Prompt libraries, system prompts, evaluation sets and any fine-tuning data included in the transfer.
• Vector database and embedding store access moved.
• Usage limits and billing on model accounts reviewed so the buyer is not surprised by the first invoice.

Revenue and customers

• Payment processor account transferred, or customer subscriptions migrated with the processor’s support. Check the processor’s own rules first.
• Billing data, MRR and subscriber counts should match the listing after the move.
• Customer database and email list transferred in line with the privacy policy.
• Transactional email, support inbox and help-desk accounts moved.
• Analytics, error tracking and monitoring accounts transferred.

Accounts and brand

• App stores and Chrome Web Store developer listings transferred. Extension and app store transfers can take days, so start early.
• Social handles, community servers and newsletter accounts handed over.
• All admin logins rotated and handed over, with a password manager export or shared vault.
• Seller removed from every account once the buyer confirms access.

Handover verification

Run a simple sign-off: the buyer logs into every item on the list, signs a one-page acceptance, and only then instructs escrow to release funds. Anything that fails goes onto a short punch list with a deadline.

Do you need an HSR filing?

Almost certainly not, but check. The Hart-Scott-Rodino Act requires premerger notification above a size-of-transaction threshold. The 2026 threshold is $133.9 million, up from $126.4 million, and the adjusted figures take effect on Feb. 17, 2026. The FTC’s announcement of the 2026 thresholds and fee schedule is the primary source.

A deal under that figure does not require a filing. Nearly every micro-SaaS and early-stage AI acquisition sits orders of magnitude below it. If you are a fund or a strategic buyer stacking several acquisitions, or a deal’s value is close to the threshold, ask your attorney how the value is calculated for HSR purposes.

Taxes and transaction costs

This is where sellers and buyers both get surprised after closing.

• Purchase price allocation. In an asset sale, the price is allocated across asset classes (software, goodwill, non-compete and so on), and the allocation affects each side’s taxes. Agree on it in the purchase agreement.
• Success-based fees. Fees paid to brokers or advisors contingent on closing have special treatment. In IRS guidance, Rev. Proc. 2011-29 provides a safe harbor election for taxpayers that pay or incur success-based fees, and a portion may have to be capitalized as part of the transaction cost rather than deducted. If a required statement is not filed, the result can be an audit or dispute later.
• Who to ask. Have your CPA review how transaction costs, including any marketplace success fee, are treated before you sign the definitive agreement. The answer depends on your entity type and on whether you are buying or selling.

Nothing here is tax advice. It is a prompt for a conversation with a CPA who handles business sales, early enough to change the paperwork.

Why deals slip after signing: the usual suspects

From the standard checklist failures to the SaaS-specific ones:

1. Undisclosed accounts. A forgotten staging server, a second Stripe account, an old app store listing. Fix: ask the seller to export a list of every SaaS login tied to the business email.
2. Contractor IP. No signed assignment from the developer who wrote the core module. Fix: get assignments before closing, not after.
3. Revenue mismatch. The listing says one MRR, the processor says another. Fix: reconcile during diligence and document the explanation.
4. Mismatched legal names. The escrow account, the agreement and the bank account must agree.
5. Vague transition terms. “Reasonable support” means different things to each party. Fix: specify hours, duration and channels.
6. Model provider terms. Some provider accounts or credits may not be transferable. Fix: check terms during diligence and plan for replacement keys.

Our perspective: closing is where marketplaces earn their fee

We built AIExchange.club for AI SaaS businesses specifically, and the pattern we see in small deals is consistent: the price conversation gets all the attention, while the closing mechanics decide whether the deal actually happens. Founders selling a side project are often not lawyers and not project managers. Buyers acquiring their first micro-SaaS have never rotated credentials on an infrastructure stack they did not build.

So we put structure around it. Every deal runs through the same six stages. Contracts are standardized and signed in the platform. Funds sit in escrow until the handover is confirmed. The fee model follows the same logic: listing is free, and we charge a flat 10% success fee only when a deal closes, with no monthly fees on the sale side. Our incentive is that deals finish.

Our advice is to write the handover list before the LOI, not after diligence. If both sides agree on what “done” looks like while they are still friendly, closing is a checklist exercise. If they leave it until the end, it becomes a negotiation.

— Phillip

Closing a deal on AIExchange.club

If you want the checklist above built into the process, start with the marketplace, where buyers browse AI SaaS listings, submit offers or join live auctions. Sellers can list a business for free. We charge a flat 10% success fee when the deal closes, and every transaction closes through escrow with standardized contracts.

Buyers who want full marketplace access can see membership options, listed at $49 per month or $399 per year, on the pricing page. If your business is larger or more complex, our Boutique AI M&A Advisory offers assisted deal support.

Planning a sale in the next year? Our 12-month sale preparation checklist and the guide on what it costs and nets to sell a SaaS business make a good companion to this one.

A one-page closing checklist you can copy

Before signing

• [ ] NDA signed
• [ ] Asset or stock structure agreed
• [ ] LOI signed with price, payment terms, inclusions, transition period
• [ ] Revenue reconciled against processor data
• [ ] Code ownership and contractor assignments confirmed

At signing

• [ ] Purchase agreement and disclosure schedules executed
• [ ] Bill of sale, IP assignment, domain assignment executed
• [ ] Seller consent or resolution signed
• [ ] Non-compete and confidentiality terms signed
• [ ] Escrow instructions agreed, names matched

At closing

• [ ] Funds deposited in escrow
• [ ] Repositories, hosting, DNS and domain transferred
• [ ] Model provider, database and vector store access moved, old keys revoked
• [ ] Payment processor, email, support and analytics moved
• [ ] App store and Chrome Web Store listings transferred
• [ ] Buyer verifies every login and signs acceptance
• [ ] Escrow released

After closing

• [ ] Seller removed from all accounts
• [ ] Transition support delivered per agreement
• [ ] Tax allocation and transaction-cost treatment confirmed with a CPA
• [ ] Customer announcement sent, if planned

Sources

• Closing Checklist: Private Mergers and Acquisitions, Thomson Reuters
• FTC announces 2026 update of HSR jurisdictional and fee thresholds
• New Hart-Scott-Rodino Filing Thresholds for 2026, Robinson Bradshaw
• Internal Revenue Service, PLR-111419-13 on success-based fees

Recommended

• Business Acquisition Steps: First Call to Close (2026)
• Due Diligence Checklist for Buying a Business: SaaS & Apps
• How to Finance a SaaS Acquisition: Real Numbers
• How to Buy an AI SaaS Business: Step-by-Step Guide