What CAS growth at Top 100 accounting firms means for client referrals

The short answer for CAS and advisory leaders

CAS growth matters for referrals less because of headline percentages and more because of what CAS work puts in front of your people: a monthly, inside view of how a client runs its finance stack. A controller-level CAS engagement touches the general ledger, bill pay, payroll handoffs, bank feeds and the apps bolted onto them, which is the same territory a data-licensing fit screen covers.

That reach comes with a duty. What your team sees under an engagement letter is confidential client information, so a CAS desk can notice that a client might fit, but the firm decides whether, when and how anyone raises it. The order on this page is deliberate: risk management first, then the client conversation, then an introduction to SourceX only with the client's permission.

Where do the Top 100 and CAS growth figures come from?

The annual Top 100 firm rankings published by the accounting trade press and the CAS benchmark survey run by CPA.com and the AICPA's Private Companies Practice Section are the usual reference points. This page does not restate their percentages: the figures change with each edition and depend on which firms responded. Read the current editions directly and note the date, the sample and the definition of CAS each one uses.

Treat survey data as strategy context, not as evidence that a client qualifies. The firm-level shift that most affects referral policy is ownership, covered in accounting firm M&A in 2026.

What do CAS teams see that data buyers care about?

CAS teams see structure and history, not just balances. AI developers building agents that complete business tasks need examples of real multi-step work, such as an invoice dispute that moved from an AP inbox through an approval to a credit memo. Those trails live inside companies and are thin on the public web.

The right-hand column is the rule. A referral partner makes an introduction and shares basic fit information; it never exports, uploads or describes confidential records.

How should a firm route a CAS-sourced introduction?

Route it so the client makes the decision, not the staff member who noticed the fit. A sequence that works in most firm structures:

1. The CAS manager notes a possible fit using metadata only: headcount band, years of history, number of systems.
2. The engagement partner decides whether the topic suits this client right now.
3. Risk management checks the client against the firm's attest and restricted entity lists; the guide to restricted entity list checks covers what to look for.
4. The firm decides whether the firm or an individual registers as the partner and how origination is booked; see origination credit and outside introductions.
5. Where firm policy requires it, the relationship passes an alliance review before anyone signs up.
6. The engagement partner raises the idea with the owner or CFO, discloses any compensation as policy requires, and asks for permission.
7. With permission, the partner sends the company a referral link so it can apply itself, or submits it through the referral form.

Two rule-level points belong in step 3. State boards regulate CPA commissions and contingent fees too, and their rules can be stricter than the AICPA Code; the New Jersey Society of CPAs' page on commissions and contingent fees shows one state's rules differing from the national code. Second, a SourceX reward is paid only if a deal closes and SourceX collects its fee, so ask whether your firm also analyzes it under the contingent fee rule. As the NYSSCPA explains, the AICPA Code treats a fee as contingent when its amount depends on attaining a specific result, and members may not perform services for a contingent fee for a client whose audit, review, certain compilations or examination of prospective financial information the firm performs.

This is general information, not legal, tax or financial advice. Confirm with your own counsel, tax adviser or professional body before acting.

Which CAS clients are worth flagging?

Flag few and flag well. CAS books mix companies of many sizes and ages, and a short list of strong candidates helps the engagement partner more than a long list of maybes. Use this CAS desk screen:

• US company with 50+ full-time employees at peak (contractors excluded).
• Several years of documented operations, with older or archived systems still reachable.
• Records spread across many systems: email, chat, shared drives, CRM, finance, support, engineering or operations tools.
• Records the company created itself, not mainly its own clients' data, consumer personal data or medical records.
• An owner, CEO, CFO or authorized representative who could sponsor a license.
• Not an attest client of the firm, or cleared in writing by risk management.

Operating, acquired and wound-down companies can all qualify if the data still exists. The who qualifies page sets out the full baseline, and the company fit checker gives a preliminary, non-binding read with no contact details required.

How does the reward work if the firm clears it?

Partners earn 25% of the eligible platform fees SourceX actually collects from the referred company's licensing deals, capped at $100,000 per referred company. Rewards are paid only after the buyer pays and SourceX receives its fee; a lead, meeting or signed agreement alone does not trigger payment, and no reward is guaranteed.

The reward comes out of SourceX's fee, so it never reduces what the client receives. Whether the firm or an individual may accept it, and how it is disclosed to the client, is a firm policy question to settle before anyone registers.

Limits and open questions

Growth figures describe firms, not clients. A rising CAS line means more monthly touchpoints; it says nothing about whether a given client holds the rights to license its records.

Demand forecasts carry uncertainty. Researchers at Epoch AI project that, if current trends continue, language models could fully use the stock of public human-written text between 2026 and 2032, which raises the value of non-public data. It is a forecast with wide error bars, not a price signal.

Clearances expire. A relationship cleared under one policy may need a fresh review after a merger, a new ownership structure or a change in a client's attest status.

Next step

Pick three CAS clients that pass the desk screen and take them to the engagement partner and risk team. If the firm clears the relationship, register as a partner and share your referral link; the overview of referral opportunities for accountants shows how other firm roles approach it.