Most limited companies buy corporate tax and statutory accounts from the same firm, and for good reason: the tax computation starts from the accounts, so splitting the work adds a handover and a risk of disagreement. What varies between firms is not the filing, which is the same job everywhere, but how much of the reliefs work is included and what happens when HMRC asks a question.
What is actually being bought
At a minimum: the corporation tax computation, the CT600 and the accompanying accounts, filed with HMRC by the deadline twelve months after the period end, and a statement of what to pay and when. Beyond that the engagement varies. Some firms include a review of capital allowances and loss usage as a matter of course; some quote for it; some do not look at it at all unless asked, and a company that has never been asked about its plant is probably in the third group.
What moves the fee
The state of the records first: a clean trial balance with a fixed asset register that agrees is a day, and the same company without them is a week. Then the number of judgements rather than computations. Associated companies, a short period, a period straddling a rate change, an overdrawn director's loan account, a property disposal: each turns arithmetic into a question, and questions are what firms charge for.
Making quotes comparable
Say what is already done and by whom, name the reliefs in play, state the associated companies count, and ask what an HMRC enquiry costs. Firms quote for different scopes otherwise and the cheapest quote is usually the narrowest one. Because nothing is published in this market, the only way to compare is to ask several firms the same question in the same words, which is what the enquiry form on this site sends.
Questions people ask about corporate tax accountants
What does a corporate tax accountant do?
Prepares the corporation tax computation and the CT600, files them with the statutory accounts, and tells the company what to pay and when. Reliefs work such as capital allowances and R&D may or may not be included.
Should the same firm do the accounts and the tax?
Usually, for compliance, because the tax computation starts from the accounts. Specialist reliefs work is the common exception and is often bought from a firm that does nothing else.
How do I compare quotes?
Give every firm the same facts: what is already prepared, the reliefs in play, the associated companies count, and ask each what an HMRC enquiry would cost. Otherwise the quotes are for different jobs.