Learning how to generate corporation tax leads is a different exercise from general accounting lead generation, because the buying trigger is fixed in advance. A limited company has an accounting reference date. Nine months and one day after that date, the tax is payable. Twelve months after it, the return is due. Those dates are recorded publicly, they do not move without a filing, and they create a predictable window in which a director becomes receptive to a conversation about who prepares their CT600.

That single structural fact changes how you build the system. Most accounting firm marketing advice tells you to publish content and wait. Corporation tax work rewards firms that know when a specific company is approaching a decision point and are visible at that moment, through search, through ads, or through direct contact.

The market is large enough that precision matters more than reach. Companies House recorded an effective register size of 4,930,634 companies at the end of March 2026, with 204,612 incorporations in that quarter alone. You cannot speak to all of them and you should not try. This guide covers how to define the slice you want, how to time approaches against the filing calendar, how to structure the search and paid layers, what goes wrong in practice, and where the data protection lines sit.

Firms usually start with a channel question. Should we run Google Ads, should we do LinkedIn, should we buy a list. The channel question is unanswerable until you have decided which limited companies you actually want.

Corporation tax clients vary enormously in profitability. A single director consultancy company with one invoice a month and a company that files group accounts with R&D claims both need a CT600. The work involved differs by an order of magnitude, and so does the fee you can defend. If your acquisition system does not distinguish between them, it will fill your pipeline with whichever type is cheapest to reach, which is almost always the least profitable one.

Filters worth applying

• Company age. Newly incorporated companies approaching a first accounting period behave differently from companies switching after five years. First timers need explanation, switchers need a reason to move.
• SIC code. Sector concentration gives you language, examples and relief knowledge that generic firms cannot match.
• Turnover band and employee count. Available on the register for filed accounts, and a reasonable proxy for complexity.
• Filing history. Late filings, dormant to trading transitions and recent accountant changes all indicate movement.

Write the profile down in one paragraph. If you cannot describe the company you want in a sentence that excludes most of the register, you do not have a profile, you have a preference. Every downstream decision, from ad copy to the questions on your enquiry form, gets easier once that paragraph exists.

The Companies House register is free to search and includes the accounting reference date, the next accounts due date, the confirmation statement date and the full filing history for every UK company. For corporation tax lead generation this is the most useful public dataset available to a UK practice, and most firms ignore it.

What the dates tell you

A company with a 31 March year end has its corporation tax payable by 1 January and its return due by 31 March the following year. The director starts thinking about it somewhere between the year end and the payment date, usually when their current accountant asks for records. That is your window. Approach three months after year end and you are early enough to be considered, late enough that the year end is real to them.

Filing history adds a second signal. A company that filed late last year, or that has just moved from dormant to trading accounts, or whose accounts have been prepared by three different agents in four years, is more likely to engage than one with an unbroken record with the same firm.

Building the working list

You can do this manually for a few hundred companies. Beyond that you need the Companies House API or a data provider that wraps it. Pull companies matching your profile, sort by accounting reference date, and segment into monthly cohorts. Each cohort becomes an outreach batch that runs on its own schedule rather than a single blast that ignores when the recipients care.

One of our clients, Chris at Thomas Emlyn Ltd, runs an outbound engine built on registry data with AI targeting layered on top. It produces thirty to fifty cold leads a month and five to ten booked meetings.

Directors search before they switch. The queries fall into three groups, and each needs a different page because each represents a different stage of the decision.

Deadline and process queries

Searches like corporation tax deadline, when is CT600 due, or what happens if I file corporation tax late. These are high volume and mostly informational. They are worth ranking for because the reader is currently holding the problem, but the page has to answer the question properly before it offers anything. A page that answers in one line and then pushes a contact form loses the position within a quarter.

Cost and comparison queries

Corporation tax return cost, accountant for limited company, changing accountants. Commercial intent, lower volume, far higher value. These readers are actively evaluating. Your page needs to explain what is included, how the process works, how the handover from their existing accountant happens, and what happens in week one.

Relief and planning queries

R&D relief, capital allowances, associated company rules, marginal relief thresholds. These attract better companies because a director researching relief has profit to plan around. They are also the queries where genuine technical depth separates you from content aggregators.

Build one page per intent rather than one page covering all three. Prads at Wings Online Filings went from five to seven enquiries a month to fifteen to sixteen, and nine new clients, in the first two and a half months of running a proper SEO architecture rather than a blog. The gain came from structure, not volume of words.

Paid search is the fastest route to corporation tax enquiries and the fastest route to wasted budget. The failure pattern is consistent and it is almost always messaging rather than bidding.

An ad that says complete accounting services for all businesses will collect clicks from sole traders, landlords, people looking for bookkeeping jobs and the occasional limited company director. Volume looks healthy, the pipeline does not. An ad that says corporation tax returns for limited companies with a March year end collects fewer clicks and more of the right ones.

Structure that holds up

• Separate campaigns by intent group. Deadline queries, cost queries and relief queries have different conversion rates and should never share a budget.
• Negative keywords do more work than bid adjustments. Exclude self assessment, sole trader, jobs, salary, courses and free templates early.
• Run three versions of every ad and change one element at a time. Comparing three variables at once tells you nothing.
• Send traffic to a page matching the query. A CT600 deadline search landing on a homepage converts at a fraction of the rate.

Measure the right things

Cost per click and impressions describe the auction. Cost per qualified enquiry, consultation to client conversion rate and average client value describe the business. Track the second set. A campaign at a higher cost per lead that produces limited company clients on annual engagements beats a cheaper campaign delivering sole trader enquiries every time, and you can only see that if the numbers connect to your practice management system rather than sitting in an ads dashboard.

Most firms lose more corporation tax leads after the enquiry than before it. The enquiry arrives at 4pm on a Thursday during a busy filing week, sits in an inbox until Monday, and by then the director has spoken to someone else.

Speed and sequence

An automated acknowledgement within a minute, a real response within the working day, and a booking link that shows genuine availability will beat almost any improvement to your ad copy. The gap between a two hour response and a two day response is measurable in conversion rate and costs nothing but configuration.

Qualification before the calendar

Not every enquiry deserves a meeting. Ask for company number, year end date, current accountant status and approximate turnover on the form itself. Company number alone lets you pull the register record before you speak, so you arrive at the call knowing their filing history, their year end and their last set of accounts. Annabel, one of our clients, screens enquiries automatically so her calendar only carries the high value ones.

The nurture that matters

A director enquiring in June about a December year end is not ready to move in June. They are ready in September. A sequence that stays useful across that gap, filing reminders, a note when relief thresholds change, a short explanation of what switching involves, keeps you present without pressure. Most firms send nothing and then wonder why the enquiry went cold.

Kieran Stocker at Swift put it plainly on Trustpilot: "Since starting with Fiscal Flow last year, we have now seen a few clients added to our portfolio, with one of them being £250 + VAT per month, producing a great ROI."

Registry based outreach is lawful and widely used, and it still sits inside the ICO's direct marketing rules. Firms that treat the register as a free list without reading the guidance create risk that is entirely avoidable.

What the ICO expects

• Tell people you are collecting and using their information for direct marketing. This applies whether the data came from your own forms, a third party list provider or a public source.
• Provide privacy information in clear, plain language at the point of collection. Just in time notices and layered notices are both acceptable.
• Explain why you want their information, whether you will share it with anyone else for marketing, and what their rights are, including the right to object.
• If you later use the data for something new, provide further privacy information rather than assuming the original notice covers it.

Practical points for accounting firms

Corporate subscriber rules for electronic marketing are different from those for individuals, and sole traders and some partnerships are treated as individuals rather than corporate subscribers. That distinction matters when your list mixes company officers with unincorporated businesses. Keep suppression lists working properly and honour objections immediately rather than at the next list refresh.

Full current guidance is on the ICO site at ico.org.uk. Read it once properly, write your process down, and the compliance question stops being a reason to avoid outbound entirely.

This is the sequence we use when installing corporation tax acquisition for a practice. Each step depends on the one before it, so resist the temptation to start with ads.

These are the patterns we see most often when a practice has been trying to generate corporation tax leads without a system behind it.