What you need to know about the new Companies House P&L filing rules

Companies House P&L filing: what mandatory accounts mean for buyers, sellers and the smallest firms

From April 2028, every UK company, including small companies and micro-entities, will have to file a profit and loss account with Companies House. The option to file abridged or cut-down accounts disappears, and all accounts must be filed digitally in iXBRL format through commercial software. Companies House confirmed the direction on 9 June 2026, settling a question that has been open since the original 2027 timetable was paused.

For anyone who buys or sells private companies, this is one of the most significant changes to the public record in a generation. It is also a compromise. Smaller companies will have to file a P&L, but they will be allowed to opt out of having it published on the public register. The result is a register that is richer for the authorities and potentially, but not automatically, richer for the market.

What has actually been announced

The reforms sit within the Economic Crime and Corporate Transparency Act 2023, the programme designed to improve data quality and make it harder to hide behind opaque corporate structures. The confirmed measures, as they affect smaller entities, are these.

From 1 April 2028, all UK-registered companies must file accounts digitally in iXBRL format using approved commercial software. Companies House web filing for accounts, and all paper filing routes, will close. Web filing will remain for non-accounts items such as confirmation statements and director updates.

View interactive listing of all government-approved filing software GO
Small companies and micro-entities will be required to file a profit and loss account, as larger companies already do. The option to file abridged accounts is removed, so small companies will file full statutory accounts including the P&L.

Crucially, small companies and micro-entities will be able to opt out of having their P&L published on the public register. The data will still go to Companies House, HMRC and law enforcement. The government has said details of how to opt out will follow.

All component parts of the accounts, the balance sheet, P&L and any directors' or auditors' reports, must be filed together in a single submission. The ability to repeatedly shorten an accounting reference period will also be curtailed.

The effective date moved from April 2027 to April 2028. That gives companies one full accounting year plus nine months, around 21 months, to prepare.

Why the timing matters to dealmakers

There is history here. A little over a year ago, the previous version of these rules looked like it was being shelved. Ministers signalled a retreat on small company filing obligations in the name of reducing red tape. At the time I argued that this was the wrong instinct, and the announcement now confirmed reads as the government recommitting to the direction of travel while softening the transparency element through the opt-out.

The reason buyers cared so much, and still do, is straightforward. When someone sets out to buy a private firm today, they are often working blind at the pre-diligence stage. Listed companies must disclose detailed financials. Private firms can keep their numbers locked away. That asymmetry shapes how deals get sourced, priced and paced.

A comparison is having a house on the market without allowing interested parties to view the interior. A published P&L does not replace due diligence, but it changes the starting point. It lets a buyer form a view on revenue, margin and trajectory before spending money on advisers and before a seller has decided how much to reveal. It widens the pool of credible targets a buyer can identify, and it makes opportunistic, well-informed approaches far more possible.

The case for transparency

I will be clear about where I stand: more financial disclosure from smaller companies is good for the market, and good for most owners too. As a qualified exit planner, my advice to owners is to get their accounts including P&L into order at least two years before a sale. Don’t be scared of transparency. Don’t obfuscate profits (or losses). Buyers pay for certainty. A clean, consistent, published track record removes friction and reduces the discount a cautious buyer applies to unknowns.

There is a wider point about company quality. I remember a director complaining online that under the first draft of the new rules (2025), a large customer could discover it was contributing 70 per cent of his revenue, and then lean on that to demand price concessions. The honest response is that a business with that level of single-customer reliance is already on a road to nowhere. Disclosure does not create the weakness, it reveals it. No serious buyer would acquire that company at a full price regardless of what the register shows. The transparency simply forces the issue earlier, which is exactly when it is cheapest to fix. In any case, under the revised rules, anyone that concerned about publicising their earnings can opt to hide their P&L from view.

The perceived benefits that accountants and commentators point to line up with this view. A richer, iXBRL-tagged register should reduce misuse of corporate shells and support economic crime enforcement. Aligning Companies House and HMRC formats should reduce duplication for businesses already on integrated software. And where a P&L is published, creditors, suppliers and lenders get better information to assess risk across supply chains.

The case for caution

It would be one-sided to stop there. The burden of these reforms does not fall evenly, and the heaviest weight lands on the smallest firms that previously filed abridged or filleted accounts.

A micro-entity that used to file a compressed balance sheet will now have to prepare and file a full profit and loss account. That raises the minimum level of record-keeping and year-end work. Companies that relied on free Companies House web filing or paper submissions will have to buy commercial software or pay an agent. For some, this is a new cash cost on top of training and process change. However the point I'd make is that a P&L already has to be submitted to HMRC, so what's the issue in also submitting to Companies House? I'd say it has more to do with no longer being able to cobble together something off a spreadsheet, with its ease of use equal to its imperfections and potential for misuse.

There is a genuine confidentiality concern. Owner-managed and family firms competing in tight local markets worry that a published P&L hands intelligence to rivals. The opt-out from publication is designed to answer exactly this, and it does soften the blow. But it is not a complete answer. Directors have to actively choose the opt-out and understand what it means. And even when the P&L stays off the public register, the data still flows to the authorities, which some owners experience as a step up in scrutiny.

The deadline risk is real and practical. After April 2028, paper and web accounts submissions will simply be rejected. A rejected filing does not stop late-filing penalties from running. A small director-managed business that leaves the change too late could find itself non-compliant and fined, not because its numbers were wrong, but because it filed them the old way.

Finally, there is a structural worry worth naming. Some owners read the opt-out as a staging post rather than a settlement, and fear that a future government could move from "file but do not publish" to full publication once the filing infrastructure is in place. That is speculation, not policy. But it is shaping behaviour, with some advisers reporting interest in partnership or sole trader structures, or in simplifying group structures, to reduce the disclosure footprint.

What owners should do now

For owners thinking about a sale in the next few years, the practical steps are the same whether you welcome the reforms or resent them.

Audit your entity list. Identify every UK company in your group, including dormant and property or asset vehicles, and confirm how each currently files.

Review your software and filing route. If you use paper or Companies House web filing for accounts, plan the move to commercial software or to filing through your accountant, and confirm iXBRL capability for Companies House, not just for HMRC.

Decide your publication stance entity by entity. Weigh the competitive sensitivity of publishing against the benefits, better access to finance and a stronger record for a future buyer, and document the decision.

Tighten your year-end timetable. Assume filings must be correct and in the right format first time, because rejected non-software filings will not pause penalties.

Take advice on year-ends early. If you are planning a restructure or a sale, the tighter rules on shortening accounting reference periods may matter, and there may be value in using current flexibility before 2028.

The bottom line

The 2028 reforms are a compromise between transparency and confidentiality, and reasonable people will land on different sides of it. The compliance burden on the smallest firms is real and should not be waved away. But the direction is right. A market where private company financials are easier to see is a healthier market for buyers, and for the well-run sellers who have nothing to hide and a track record worth showing. For any owner with a sale in mind, the message is simple.

Do not treat April 2028 as a compliance deadline to scramble against. Treat it as a prompt to get your numbers clean, consistent and ready to stand up to scrutiny well before you ever go to market.

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