ONESOURCE Implementation
and Support
Tax Provision, Corporate Tax, Statutory Reporting and DataFlow, implemented and supported by Thomson Reuters Certified Implementers.
Certified across the suite
Osprey Consulting is a Thomson Reuters ONESOURCE Certified Implementer for Tax Provision, Corporate Tax, Statutory Reporting and DataFlow, with a certified implementer on every implementation.
From inside Thomson Reuters
Mark was Director of Solution Consulting at Thomson Reuters, where he oversaw the consulting team for the ONESOURCE platform.
You work with the founders
Directly with Mark and Charlotte throughout, with no handoffs to junior consultants.
One Platform. One Connected Close.
ONESOURCE Statutory Reporting, Corporate Tax and Tax Provision each do one job in the close. Connected, the work is done once. The trial balance is finalised in Statutory Reporting and passes into the Corporate Tax computation. Tax Provision draws on that same computation, so the UK tax logic is not rebuilt. The tax disclosures then come back into the accounts.
General Ledger Manager supplies the trial balance, ONESOURCE DataFlow collects what the ledger does not hold, and Workflow Manager tracks each step so the close is visible from one place. See ONESOURCE DataFlow.
The products connect in different ways: some directly, others through APIs or ONESOURCE Workpapers. We design and build those connections, not just the products themselves. If you are considering more than one, implementing them together is typically more efficient than separate projects.
ONESOURCE Statutory Reporting
Automated statutory financial statements at scale - global templates for large multinationals and Companies House digital filing readiness for UK groups ahead of the 2028 mandate.
ONESOURCE Statutory Reporting (OSR) replaces manual, Word and Excel-based statutory accounts production with a structured, template-driven process. For large multinational organisations, we configure the TR global account templates that produce consistent financial statements across dozens or hundreds of entities - with disclosures populated directly from trial balance data and local formatting applied automatically.
For UK groups, mandatory software-only filing at Companies House applies to annual accounts filed on or after 1 April 2028. Confirmed by the government on 9 June 2026 (after the original 2027 timetable was paused), it requires all accounts to be filed in iXBRL format using commercial software, with the existing web and paper filing routes for accounts closing. OSR - with its built-in iXBRL tagging and Companies House integration - is the natural platform for organisations that need to be ready. We implement OSR as a standalone solution or fully integrated with ONESOURCE Corporate Tax, covering everything from template design and data integration through to digital filing configuration and team enablement.
Full ONESOURCE Statutory Reporting implementation details → Collecting data from your entities first? See ONESOURCE DataFlow → Discuss This ServiceWhat We Deliver
- Global statutory accounts template configuration and build
- Chart of accounts mapping to disclosure categories
- Trial balance and ERP data integration
- iXBRL tagging for HMRC and Companies House digital filing
- Companies House digital filing readiness (2028 mandate)
- Multi-entity and multi-territory configuration
- Integration with ONESOURCE Corporate Tax
- Review workflow and sign-off process design
- User training and post-implementation support
ONESOURCE Corporate Tax
Corporation tax compliance automation - tailored templates, streamlined review workflows, and clean data feeds delivering a faster, more reliable return process.
ONESOURCE Corporate Tax (OCT) automates the preparation, review, and approval of corporation tax returns. It replaces manual spreadsheet processes with structured, repeatable workflows - reducing the risk of errors and freeing your team to focus on higher-value advisory work.
We implement OCT from initial setup through to go-live, building return preparation templates tailored to your group structure and configuring data feeds directly from your ERP. We design the review and approval workflow around how your team actually operates - building in the controls and process improvements that reduce time in each compliance cycle.
Full ONESOURCE Corporate Tax implementation details → Collecting data from your entities first? See ONESOURCE DataFlow → Discuss This ServiceWhat We Deliver
- Entity configuration and chart of accounts mapping
- Automated data feeds from ERP and ledger systems
- Corporation tax computation configuration
- Return preparation template design and build
- Review and approval workflow design
- Disclosures and supplementary page configuration
- Process improvement and workload reduction review
- User training and team enablement
- Ongoing support and software updates
ONESOURCE Tax Provision
End-to-end implementation of ONESOURCE Tax Provision for multinational group reporting.
ONESOURCE Tax Provision (OTP) is the market-leading platform for group tax provision and reporting for multinational organisations. Osprey Consulting has deep, hands-on expertise across the full OTP implementation lifecycle - from initial scoping and data analysis through to configuration, integration, testing, and go-live.
Mark Hart spent years as Director of Solution Consulting at Thomson Reuters, where he oversaw the consulting team for the ONESOURCE platform. That experience means we understand both the technical platform and the real-world tax requirements it needs to meet.
Full ONESOURCE Tax Provision implementation details → Discuss This ServiceWhat We Deliver
- Requirements analysis and system design
- Chart of accounts mapping and data transformation
- ERP and TB data integration (API, file-based, Alteryx)
- Current and deferred tax configuration
- Jurisdictional rules and apportionment logic
- Return-to-provision and true-up workflows
- Report design and published output
- Parallel-run testing and sign-off
- User training and knowledge transfer
- Post-go-live hyper-care and support
ONESOURCE DataFlow
Collect data from every entity once, and report across all of it.
Every year the same request goes round, asking the legal entities for data that no system can give you. ONESOURCE DataFlow replaces the emailed spreadsheet with one standard template for every entity, with validation and controls, rolled forward each year, and the data held centrally so you can report across all of it.
Thomson Reuters ship the engine and the template is yours, built in Excel around the process your business actually runs. Once the collection is right, APIs and AI can be added on top. Our nine minute walkthrough shows one example. Delivered by a Thomson Reuters ONESOURCE DataFlow Certified Implementer.
Full ONESOURCE DataFlow implementation details → Discuss This ServiceWhat We Deliver
- Requirements and process design, starting from the process you run
- Template build in Excel, with your validation rules and controls
- Trial balance integration from General Ledger Manager or another source
- Roll forward design, so next year starts from this year
- Cross request reporting across every entity
- Integration by API with any API enabled system
- Optional AI classification, with rules your team edits
- Documentation and training, so your team maintains the workbook
ONESOURCE Support
Responsive, expert help with the systems we implement, alongside your vendor agreement, plus cover when your team is stretched or in transition.
Your Thomson Reuters agreement looks after the platform. We look after everything specific to you: how your ONESOURCE set-up is configured, how your data gets in, how your close runs, and whether your team can run it with confidence. You reach the consultant who knows your configuration, not a helpdesk, and we try to answer the same working day.
It is practical help in live situations, from covering a tax team member through year end and accounts season to answering ad hoc questions on ONESOURCE Corporate Tax. And when the person who understood the system moves on, we are the bridge: keeping the close on track and bringing their successor up to speed on your own set-up. Alphatax and Alteryx are covered on the same basis.
Full ONESOURCE Support details → Discuss This ServiceWhat We Deliver
- Direct answers on your configuration, usually the same working day
- Configuration changes, new entities, mapping and rate updates
- Close-time cover during provision, compliance and statutory peaks
- Bridging cover and knowledge capture during staff transitions
- Health checks on set-ups implemented by others, or that the business has outgrown
- Refresher and new-joiner training on your own configuration
- Retained hours or a monthly arrangement, far less than a full-time hire
Checklists, guides and walkthroughs
We have a number of pre-built connections
Between the ONESOURCE products, and between ONESOURCE and the systems around it. Watch them working, in a minute or two each:
1 min 28 sec Every trial balance, into Statutory Reporting → 
1 min 27 sec Trial balance to Tax Provision, in Alteryx → 
1 min 1 sec Corporate Tax to Tax Provision, automated → 
1 min 58 sec Tax disclosures, automated in Alteryx → 
1 min 6 sec Trial balance to Statutory Reporting, with Python → 
44 sec ONESOURCE DataFlow in 44 seconds → ONESOURCE: frequently asked questions
Are you ONESOURCE consultants and an implementation partner?
Yes. Osprey Consulting is a UK based, authorised Thomson Reuters ONESOURCE implementation partner and a Certified Implementer for ONESOURCE Tax Provision, Corporate Tax, Statutory Reporting and DataFlow. A certified implementer works on every implementation.
Which ONESOURCE products do you implement?
ONESOURCE Tax Provision, Corporate Tax, Statutory Reporting and DataFlow. We implement each on its own or together, and we design and build the connections between them.
Do the ONESOURCE products connect to each other?
Yes, in different ways: some directly, others through APIs or ONESOURCE Workpapers. We design and build those connections, not just the products themselves. Two of the connections we have built, in short videos:
The connected close in 30 seconds →Corporate Tax to Tax Provision, automated (1 min) →Tax disclosures from Corporate Tax into Statutory Reporting (2 min) →
Can data be loaded into ONESOURCE, and read back out, by API?
Yes. ONESOURCE Statutory Reporting, Corporate Tax, Tax Provision and DataFlow each have APIs. We use them to load trial balances and journals, to move computations and disclosures between the products, and to read data out for reporting, from Alteryx, Python or whatever your team already runs. Three examples, in short videos:
Every trial balance into Statutory Reporting by API, with Alteryx (1 min 28 sec) →The group trial balance into Tax Provision by API, with Alteryx (1 min 27 sec) →A trial balance into Statutory Reporting with a Python script (1 min 6 sec) →
Do you provide ONESOURCE support after go-live?
Yes. Every implementation includes a hyper-care period, and beyond that we offer ongoing support that works alongside your Thomson Reuters agreement: direct answers on your own set-up, configuration changes, close-time cover and bridging cover during staff transitions.