For firms · 3 min read · Updated 12 November 2026 · By Jess Luper
Submitting returns? Check them before you file.
For financial institutions that send regulatory returns: banks, building societies, insurers and investment firms. Check a return free, in your browser, against your regulator’s own rules. Or have Line4 do the whole job, every period.
- Banks
- Building societies
- Insurers
- Investment firms
Two ways to work with Line4
Start with the free check. When you want every return done for you, move to Managed Reporting. Both come from Line4 Ltd, a UK company.
Line4 Check
The web check. Choose your regulator and return, and check a file before you submit it.
- Your regulator’s published rules, run on your file in seconds
- No account, no sign-up and no limit
- Your file never leaves your computer
- Every check, run or not, in the public coverage ledger
Line4 Managed Reporting
For firms that want the whole job done.
- Every return, every periodEach return prepared, checked and evidenced, ready for your sign-off.
- Rules kept up to dateUpdated with every taxonomy release your regulator publishes.
- SupportHelp for your team when a return or a check raises a question.
- A named contactOne person at Line4 who knows your returns.
Line4 Ltd · Registered in England and Wales · Companies House 17308895 · team@line4.ai · About Line4
What you can check today
Line4 Check runs each regulator’s own published validation rules. We only mark a framework as live once it runs those rules and we have tested the results.
- Banks and investment firms in the EU and EEAEBA returns42 modules of EBA reporting framework 4.2, with filings for 4.0, 4.1, 4.2.1, 4.3 and 4.4 phase 1 checked against their own release’s rules.LiveCheck a file →
- Insurers in the EU and EEASolvency II QRTs (EIOPA)9 returns on EIOPA taxonomy 2.8.2 and 2.10.0.LiveCheck a file →
- UK insurersSolvency UK returns (Bank of England)5 quarterly and annual returns to the PRA.LiveCheck a file →
- UK banks, building societies and investment firmsPRA banking returns (Bank of England)24 returns on the Bank of England banking taxonomy 4.1.1, including the new SDDT returns.LiveCheck a file →
The coverage ledger lists every check, run or not, with the reason for each one not run. Filing with another regulator? Tell us which one you need.
UK building societies and small banks
New returns from 1 January 2027.
Small domestic deposit takers (SDDTs), most of them building societies, report own funds on new, shorter templates (PRA116), and capital forecasts on PRA117 or PRA118.
Line4 Check already runs 529 of the Bank’s 531 active validation checks for PRA116, all 13 for PRA117 and all 9 for PRA118 on taxonomy 4.1.1, free. Or have Line4 prepare and check them every period with Managed Reporting.
A check at submission is step one of real-time supervision.
When a return is checked before it is filed, mistakes are fixed while the figures are fresh. What reaches your regulator is right when it lands.
Step two is firms’ systems sending returns straight through, checked the moment they are sent. We expect most supervisors to want that by 2030. Line4 builds both sides: the check for firms, and the platform for regulators.
Questions
- Who is this for?
- Banks, building societies, insurers and investment firms that send regulatory returns in XBRL. Line4 Check covers EBA returns in the EU and EEA, Solvency II QRTs, Solvency UK returns and PRA banking returns today. We add regulators one at a time, starting with the ones firms ask for.
- Is the check really free?
- Yes. The web check is free and stays free: no account, no sign-up and no limit. It runs in your browser. Your file never leaves your computer.
- What is Line4 Managed Reporting?
- Line4 Managed Reporting is for firms that want the whole job done: one price for a managed service and a support contract. Each period, every return is prepared, checked and evidenced, ready for your sign-off. The rules are updated with every taxonomy release, and you get support and a named contact at Line4 who knows your returns.
- How much does Managed Reporting cost?
- One price covers the managed service and the support contract. It depends on the returns you file, so we agree it on a call first. There is no public price list.
- When is the first PRA116 due?
- For the quarter ending 31 March 2027, by 12 May 2027. PRA116 is the new own funds return for small domestic deposit takers (SDDTs), most of them building societies, from 1 January 2027. SDDT reporting, explained.
- Is a check the same as my regulator’s validation?
- No. It catches problems before you submit. Your regulator’s own validation decides whether a return is accepted, and it can run checks Line4 Check does not. The coverage ledger lists every check Line4 Check does not run, and why. See the coverage ledger.
- Who is Line4?
- Line4 Ltd, a UK company registered in England and Wales (Companies House 17308895). Line4 builds SupTech for financial regulators, and Line4 Check and Line4 Managed Reporting for the firms that report to them.
Our view
RegTech and SupTech are converging on real-time supervision by 2030. Line4 is built for that: checks at the gate in seconds, AI you can audit, and a switch that takes a week.