Working with CASS

What it costs and what moves the price, how switching works, onboarding and the first 90 days, and who does the work.

These answers provide general information, not advice tailored to your circumstances. Rules can change and exceptions may apply — speak to the CASS team before making a tax, accounting or financial decision.

Contact us before the deadline where possible. We can help you understand the amount due, review the position and discuss HMRC payment options, although HMRC decides whether to agree a plan.

Last updated 29 September 2026

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