Client advisory services, or CAS, is a practice area in accounting where a firm advises clients across financial and business decisions, forward-looking rather than compliance-focused, and typically billed separately from tax and bookkeeping work. It is the fastest-growing service line in public accounting relative to firm-wide revenue growth.
Glossary · Page 19
Client Advisory Services (CAS)
How CAS is defined
CPA.com, the technology arm of the AICPA, defines CAS as "a practice area that helps clients outsource business needs with services spanning a spectrum of accounting, financial and advisory-related offerings," with the stated goal of "firms maximizing value to their clients and becoming the trusted advisor" (CPA.com). An earlier CPA.com framing describes CAS as helping firms "advise clients across a spectrum of financial and accounting related decisions, with the goal to deliver higher value and deepen the trusted advisor relationship" (CPA.com).
The distinguishing test is not the deliverable's format. It is whether the client is paying the firm to look forward and act, rather than to report on what has already happened.
What counts as a CAS service
CPA.com's own CAS marketing toolkit lists common services under the CAS umbrella, including financial statement preparation, CFO or controller advisory, forecasting and budgeting, management reporting, business performance reviews, profitability consulting, strategic planning, and benchmarking (CPA.com). AICPA's own framing describes firms that "advise clients in various financial and accounting-related decisions and strategies," increasingly enabled by automation, AI, and cloud tools (AICPA & CIMA).
The contested acronym
CAS most commonly stands for Client Advisory Services, the term CPA.com and AICPA use in their own published materials (CPA.com). Some firms and vendors instead use Client Accounting Services, or the combined term Client Accounting and Advisory Services (CAAS). All three refer to overlapping practice areas; there is no single universally enforced definition across the industry.
How fast CAS is growing
CAS practices reported 17% median revenue growth in a recent measured period, compared to roughly 6 to 9% median growth for firms overall in the same period, according to the AICPA/CPA.com Benchmark Survey (Journal of Accountancy; AICPA/CPA.com). That gap is the reason CAS is frequently described as the fastest-growing service line in public accounting.
For a full walkthrough of what counts as advisory work, how to price it, and how to test the advisory motion inside a traditional firm without buying an expensive platform, see add advisory services to your accounting firm. To see how a diagnostic can open an advisory conversation with a specific client, start the Profit Wizard.
Frequently asked questions
Does CAS replace compliance work like tax prep and bookkeeping?
No. CAS is typically layered on top of existing compliance work, priced and delivered separately, rather than replacing it.
Is CAS the same thing as being a fractional CFO?
Not exactly. Fractional CFO work is one recognized service inside the broader CAS category, alongside forecasting, KPI dashboards, and strategic planning. CAS is the umbrella practice area; fractional CFO work is one offering within it.