CODEx: Accelerating the use of Structured Data in the UK

Published: 30 May 2025

Welcome to the final report for the CODEx project.

Foreword

I am pleased to present our final report on the CODEx project.

When we applied for the project funding in mid-2022 we wanted to find innovative and cost-effective ways of accessing and using the structured accounting and reporting data that we have enabled for many years in the UK. We had a conviction that if we succeeded it would not only support cross regulatory activities and policy making but also create new opportunities for businesses and investors to make more informed decisions.

With the completion of the project, we have achieved our objective. Our public XBRL Viewer has made structured reporting data more accessible and more transparent, and our Regulatory Toolkit provides us with the tools we need to give better regulatory and policy insight. 

These innovative outcomes would not have been possible without the funding provided by the Regulators’ Pioneer Fund. I want to thank the team at DSIT for the opportunities the funding brought, and the support given throughout the project. Without it, it would have been difficult to take on such a project where the public benefit is so clear, but the data and the know-how stretches across (and beyond) regulators and agencies. By regulators working together, we have built an important component that underpins a digital future for UK company reporting, supports growth and demonstrates innovation in practice.

Mark Babington

Mark Babington

Executive Director of Regulatory Standards

CODEx is a project that revolutionises the use of structured company data in the UK.

The project delivered public tools, infrastructure, blueprints and skills that serve to embed structured data at the heart of company reporting. By enhancing transparency for the public and empowering data-driven decision-making, this project supports economic growth and boosts the effectiveness and efficiency of regulators and agencies.

Project details and context

The FRC, supported by Companies House, FCA, The Charity Commission, HMRC and others, launched the 18-month Company and Organisational Data Explorer ("CODEx") Project in September 2023 with the aim of accelerating the use of structured financial data. The project was supported by funding from DSIT as part of the Regulators’ Pioneer Fund (RPF). The project was led by the FRC but aimed to be relevant across a group of regulators.

What issue did the CODEx project aim to address?

The UK has a focus on economic growth, support for longer-term investment and a drive to maintain and enhance the UK’s capital markets. A key enabler for all these goals is a data ecosystem that provides useful insights to the widest audience and at the lowest cost. To achieve this, it is critical to enable access to both the data and the tools to analyse the data.

The UK is a world leader in collecting company and organisational data in structured digital form in the iXBRL (Inline eXtensible Business Reporting Language) format. Of the 3.1 million accounts published annually on the Companies House register, 88% are available in iXBRL format. In addition, more than 500 issuers on regulated markets file their annual reports in iXBRL format with the FCA.

Access and usability of the data has been challenging – data is contained in regulatory silos and is not in a form that is easy to view and analyse. This limits the public and regulatory value of the collected data and adds potential complexity and cost when the public, investors, regulators and government agencies are consuming such data.

How we looked to solve it?

The outputs of the project are focused on building capability and capacity around structured data and included: 

  • A public element being an iXBRL (Inline eXtensible Business Reporting Language) Viewer (the Viewer) – a tool to display individual or a small number of iXBRL files, showing the tags in the context of the human-readable report, and
  • A private element being a regulatory and agency Toolkit (the Toolkit) – a series of data capability sessions to develop skills, blueprints, and tools for bulk data analysis.

Our process

In this section:

About the process

As a government supported project, we adopted a best practice, agile approach to project delivery with the project split into 4 phases: (Pre-)Discovery, Alpha, Beta (Private and Public).

Phase Viewer Toolkit

Pre-Discovery

(February 2023 to September 2023)

The initial phase focused on understanding the opportunity and feasibility of solutions. The team engaged with the regulatory community and the public to identify how structured reporting data could be used and improved. This led to the decision to develop two main elements: the Viewer and the Toolkit.

See the Viewer entry.

Discovery

(September 2023 to January 2024)

User research was conducted to understand the needs of various user groups, including regulators, investors, and the public. The research identified key user needs such as efficient information retrieval, understanding iXBRL tags, easy access to company reports, and exporting data for offline analysis.

The team developed a blueprint for the Toolkit, focusing on enhancing data analysis capabilities, improving data accessibility, and facilitating data sharing and collaboration.

Alpha

(February 2024 to July 2024)

Prototypes were developed and tested, focusing on the core user journey through the Viewer. The FRC procured digital specialists to build the technical architecture and design a user interface that met accessibility and usability standards.

A proof-of-concept for parsing XBRL data was developed using both commercial and open-source tools. The team decided to proceed with a commercial offering due to its practicality within time and budget constraints.

Beta

(August 2024 to March 2025)

The Beta phase was split into Private and Public Beta phases. Feedback from users was incorporated to enhance the Viewer’s functionality. The Viewer was launched to the public, providing access to 30 million annual reports in iXBRL format.

The Toolkit MVP was developed, ingesting iXBRL data from various sources and transforming it into a data model. Workshops were held to test the Toolkit’s value and gather feedback for further improvements.

What we built

The project’s first aim was to understand both what the opportunity was as well as the feasibility of solutions. We worked with the wider regulatory community to understand how structured reporting data could be used and with the public to understand how they currently engaged with the data (if at all) and how this could be improved.

This work drove us to conclude that the best approach was to focus on two elements:  a public element being an iXBRL Viewer (the Viewer);  and a private element being a regulatory and agency Toolkit (the Toolkit).

CODEx workstreams

Inline XBRL Viewer

What is it?

A web enabled tool that supports users to search and display individual iXBRL tagged annual reports, showing the individual financial tags in context, and supporting their use and reuse.

Key elements

  • Open source Government-grade accessibility and security.

Who is it for?

  • General public
  • Investors
  • Companies
  • FinTechs
  • Academics

Experimental Regulatory Toolkit

What is it?

A data platform that allows he bulk analysis of XBRL data to identify companies with specific or outlier values.

Key elements

  • Data sandbox
  • Data sprints to develop tools
  • Blueprint to support future use

Who is it for?

  • Regulators
  • Standard Steers
  • Policy Makers

Output: Viewer

About the Viewer

The UK iXBRL Viewer, is a new tool designed to improve free access to structured company reporting data.

The Viewer enables users to easily view and analyse Inline eXtensible Business Reporting Language (iXBRL) files, displaying tagged data within reports. This innovative tool represents a significant step forward in making company financial information more accessible and transparent to stakeholders.

“We welcome the launch of this new tool which makes it easier to view and analyse structured financial information in the companies register. We are committed to becoming a fully digital filing service and improving the quality of our data to benefit the economy.”

Louise Smyth, Chief Executive of Companies House

Give the Viewer a try

Viewer in numbers

Viewer statistics
Feature Numbers
Annual Reports available via the Viewer 11m
Searches performed in March 3,353
Index page requests 5,633

See the Viewer in action

Watch our short video of the Viewer in action.

Output: Regulatory Toolkit

About the Regulatory Toolkit

Using the Viewer is a great way of looking at specific data points within an annual report, but we also wanted to build capacity to use the data en-mass to support our understanding of trends, identify quality issues and provide analysis that supports policy. To do this we built a Regulatory Toolkit.

What is it?

The Toolkit is a data platform which brings together company data from public sources (Companies House and the FCA), processes the data into a database, adds reference data and serves it up to users via a series of data visualisations. The visualisations are designed to support regulators in answering questions, investigating current practice and supporting the monitoring of data and accounting quality.

How does it work?

We wanted to create a Toolkit that, where possible, made use of common standards, tools and components. We therefore built the Toolkit using tried and tested technology that were easy to use and support. We wanted to ensure that it was simple for users and required little additional knowledge, whilst still providing data teams with more complex options.

Diagram showing the three inputs (FCA NSM iXBRL Accounts files; Reference data such as industry and FX; Companies House iXBRL Accounts files including charities) feeding into a SQL database (Listed Company Data Model and Non-Listed Organisation Data Model). The database interacts with Excel Power Query and PowerBI Semantic Model to output to the Viewer.

The Toolkit makes use of common standards, tools and components such as SQL databases, PowerBI and Excel

Who is it built for?

  • Policy staff - analysis of structured data would support them in their role to analyse reporting practice under current rules; and assess the impact of future policy.
  • Supervision staff - analysis of structured data would support them in their role to identify non-compliance in companies' or auditors' reporting; and make a risk-based sample selection to support efficient use of resources.

What can it do?

  • Support regulators and agencies in their bulk analysis of XBRL data to identify companies with specific or outlier values by:
    • Identifying the population of companies meeting certain size criteria (e.g., Public Interest Entities)
    • Identifying and analyse companies with specific values for certain XBRL tags (e.g. assets, liabilities, income or expenses)
    • Analysing and visualise the values of specific XBRL tags for companies in a particular industry or share index (e.g. FTSE 100)
    • Identifying the companies who are applying a particular rule or standard
    • Assessing companies against custom risk indicators (e.g. liquidity, solvency, impairments, filing date, auditor etc.)
  • Support regulators and agencies in there quality review of annual reports after submission, by:
    • Checking whether required annual report disclosures have been provided
    • Identifying tagging errors (e.g. unusually large amounts, extensions or unexpected signs)

What is in it?

See the Toolkit in action

Watch our short video of the Toolkit in action.

Supporting others in developing tools

Whilst the Regulatory Toolkit itself is not public we wanted to facilitate and support others who may want to achieve something similar, as such we will provide some additional helpful material in due course.

Key outcomes

With a project such as CODEx the outcomes are a mixture of the physical tools we developed and the legacy that project generated in terms of ideas, connections and engagements.

For regulators, the Toolkit and Viewer fill an existing gap in allowing us to receive and analyse the structured accounting information at scale. The FRC sets the standards but has not, until now, been able to review and utilise the resulting data. These products align with our growth priority of identifying and preparing for future trends and innovations, enabling the UK to play a leading role in the use of reporting technology.

Similarly, the public has been able to access digital annual reports (from Companies House and the FCA) but have not been able to see or use the structured accounting data within these files. The Viewer allows for that data to be used, supporting economic decision making and underpinning investor and broader confidence in UK plc further supporting our growth duty.

Published: 30 May 2025