Sell into one member firm and one service line at a time. Find a partner whose clients have a problem your product solves, clear the independence check and security review early, and sign a statement of work with acceptance criteria. Each country in a Big 4 network is a separate legal entity and a separate sale.

Why does a Big 4 deal start in one country?

Each member firm buys for itself. Deloitte's own description reads: "DTTL and each of its member firms are legally separate and independent entities." The same page says Deloitte Global does not provide services to clients (Deloitte, October 2026).

The budget is large and spread out. Deloitte reported $70.5 billion of global revenue for the year to 31 May 2025 (CPA Practice Advisor, October 2025), earned by member firms and their service lines. A contract with the US firm gives you no rights in the UK firm. Land in one country, prove usage there, then ask the sponsoring partner to introduce you to their counterpart in the next one.

Who is the first buyer inside the firm?

The first buyer is a partner who runs a service line and sees a client problem every week. Tax partners serving private clients, audit partners who test large transaction volumes and advisory partners on deals or forensic work each own revenue and can sponsor a tool. Innovation and digital teams can run a pilot. The service line partner decides whether the tool reaches client work.

Open with the client problem and the revenue it adds to the partner's practice. A partner will spend political capital on a tool that wins or keeps client work. A tool that only cuts internal cost usually goes to a central technology team, which moves slower.

We built this sales process at Koinly from zero. It took ARR from $0 to $300K in 18 months, closed 9 enterprise accounts from the Big 4 to Wealthsimple, including Deloitte, BDO, Mazars and RSM, and held a 48% demo-to-close rate across the enterprise book. These are figures from our time at Koinly, as published on our enterprise page.

What does the independence check mean for a vendor?

Ask about audit relationships in the first meeting. Under SEC Rule 2-01(c)(3), an accountant is not independent if the firm has a direct or material indirect business relationship with an audit client. The rule excludes relationships where the firm provides professional services or is "a consumer in the ordinary course of business" (17 CFR 210.2-01).

For a vendor, the practical reading is this. If the firm audits your company under SEC rules, it can usually still buy your software on standard terms as an ordinary customer. A joint go-to-market deal, a resale agreement or a referral fee is a business relationship, and the firm's independence team can refuse it. Private-company audits fall under the AICPA code, which has its own rules on business relationships. A partner who learns of an audit link late may have to unwind a deal that legal already approved, so list your auditors, investors and board members early.

What does the review sequence look like?

Expect five gates. Prepare each pack before the gate opens.

Gate Owner What they ask What to have ready
1. Sponsor Service line partner Which client problem it solves and what revenue it adds One-page use case built on a real client scenario, with no client named
2. Independence Independence or risk team Your relationships with the firm and its audit clients List of your auditors, investors, lenders and board members
3. Information security IT security Data flows, hosting location, access controls, certifications Completed security questionnaire, SOC 2 or ISO 27001 report if you hold one
4. Legal and procurement Procurement and legal Liability, data processing terms, supplier onboarding Statement of work with acceptance criteria and named deliverables
5. Rollout Sponsor plus training team Who trains staff and who supports them Training plan and a named contact for the first 90 days

Acceptance criteria do the most work. A statement of work that defines what counts as delivered gives procurement a clear yes, and gives the sponsor cover inside the firm. At Koinly, statements of work with acceptance criteria were the discipline that closed Deloitte, BDO, Mazars and RSM.

How do mid-tier firms buy differently?

Many mid-tier firms now have a private equity owner and a split structure. Grant Thornton US closed the sale of a stake to New Mountain Capital on 31 May 2024. Grant Thornton LLP now provides attest services, and Grant Thornton Advisors LLC provides advisory and non-attest services. The firm said the deal funds acquisitions and investments in technology and people (CPA Practice Advisor, June 2024).

Three things change for a vendor under that structure:

  1. The budget may sit in the advisory company. Ask which entity will sign for a tax or advisory tool, because the signing entity sets the procurement path.
  2. The owner looks at revenue per professional. Show how the tool lets each person serve more clients or sell a new service.
  3. Buying centralises. As the platform acquires smaller firms, it moves them onto one stack. One platform deal can cover many acquired offices, and one lost deal can remove you from all of them.

In our experience, mid-tier firms also have fewer review layers than the Big 4. The partner who sponsors a pilot often sits one or two levels from the person who signs.

What should a vendor do before the first meeting?

Run this checklist:

  1. Pick one member firm and one service line, and name the partner.
  2. Write the use case as a client problem with a revenue figure attached.
  3. Ask whether the firm or any firm in its network audits you or your investors.
  4. Send the security pack before the second meeting.
  5. Draft the statement of work with acceptance criteria before procurement asks.
  6. Agree with the sponsor which partner in the next country they will introduce.

Large firms treat vendors the way other regulated buyers do, a pattern we also cover in how crypto infrastructure firms book meetings with institutions.

To map which partners in which member firms own your use case, start with The Diagnostic at $2,500.