Tax
Global minimum tax platform: calculate and file, without the spreadsheets
- Client
- A UK tax-technology software provider (name withheld)
- Sector
- Tax, Compliance, Financial Regulation
- Scale
- Built for €750m+ multinational groups
A new international framework, the OECD's Pillar Two, requires large multinational groups to pay a minimum 15% tax and file in every country they operate in, and it is extremely complex to calculate. We were brought in to deliver functionality on the platform that handles the whole calculation for a group and produces the filing in the format each country requires, so tax teams can meet their obligations without wrestling spreadsheets.
Technologies
- .NET
- C#
- SQL Server
- Azure
- Angular
- REST APIs
The challenge
In 2024 the OECD introduced a new international tax framework known as Pillar Two: a minimum 15% tax on large multinational groups, those with revenue above €750 million. It is one of the most complex pieces of tax regulation in years. To comply, a group has to pull together the financial and tax figures for every company it owns, work out the effective tax rate in each country it operates in, and calculate a top-up tax wherever that rate falls below 15%. The rules are new and still evolving, and every country has its own format for how the final return must be submitted. The first filing deadlines arrived in 2026, and most companies were trying to manage all of this in spreadsheets that do not scale and leave no reliable trail.
Our approach
We were brought in to deliver functionality on the platform, contributing to design decisions and building the parts tax teams rely on.
- The whole group in one place. Companies map out their group structure, all the subsidiaries and how they fit together, and enter their tax figures once, instead of stitching them together across spreadsheets.
- Every calculation handled for them. From there the platform does the hard part: it works out the effective tax rate in each country, calculates who in the group owes what, and figures out any top-up tax due. The complex Pillar Two rules are handled inside the app, and built so they can be adjusted as the official guidance keeps changing, so the platform keeps pace.
- Filed in the right format, with a full audit trail. At the end it produces the return in the exact format the country being filed in requires. We also built in a complete audit trail, so every edit by every user is tracked and the full history behind each figure can be seen, which matters when the numbers have to stand up to a tax authority.
The result
Tax teams can calculate their global minimum tax with confidence instead of wrestling spreadsheets. All the calculations are handled inside the platform, every number can be traced back through its full history, and the finished return comes out in the format each country requires, ready to file. It gives multinational groups a controlled, defensible way to meet a brand-new obligation and hit their filing deadlines.
