What are client accounting services?

Client accounting services, or CAS, is an accounting firm running a client's finance function as an ongoing service: bookkeeping, bill pay, payroll, month-end close and management reporting, often up to fractional controller or CFO work. It is the fastest-growing service line at US firms and the main target of the AI accounting agent companies.

Definition

Monthly recurringBilling model

Ledger, capture, close, billingKey tools

Practice managementCategory

CAS turns a firm from a once-a-year compliance provider into the client's outsourced finance team, billed monthly. It depends on technology: a shared cloud ledger, automated data capture, bill pay and payroll tools, and increasingly agents that do the bookkeeping so staff can review. Basis, Accrual and Clark sell agents to CAS practices; Keeper, now Double, and Karbon run the workflow; Ignition and Anchor handle the billing. Firms that scale CAS report it as their highest-growth and highest-margin line.

Common questions

What is the difference between bookkeeping and client accounting services?+

Bookkeeping records transactions. CAS includes bookkeeping and adds the rest of the finance function: close, reporting, payables, payroll and advisory, as one recurring engagement.

Why are firms investing in CAS?+

Recurring revenue, higher margins than compliance work, and a closer client relationship. Talent shortages make automation essential to grow it.

Which technology supports a CAS practice?+

QuickBooks Online or Xero as the ledger; Dext for capture; BILL for payables; Double, Karbon or TaxDome for workflow; Basis or Accrual for agent-driven work; Ignition or Anchor for billing.