Senior Group Accountant (H/F)

About Horizon Trading Solutions

Horizon Trading Solutions (HTS) is an international FinTech company specializing in electronic trading solutions for financial institutions worldwide. With approximately 160 employees across Europe, North America, the Middle East and Asia-Pacific, Horizon supports clients in over 26 countries. B Corp certified since 2022, HTS has also received several industry awards, including Best Sell-Side EMS 2026, Best Sell-Side OMS 2025 and Best Multi-Asset Trading System 2025. As we continue to grow internationally, we are strengthening our finance function to support our global operations.

The role

Horizon Trading Solutions (HTS) is hiring a Senior Accountant to bring accounting processes in-house, strengthen compliance with international accounting standards and external reporting requirements, and implement new tools (systems of record / automation). We currently work with external accountants; you will lead the operational transition and build the processes, controls and systems that give HTS reliable financial information.

This is a hands-on role with scope to shape how accounting works at HTS. You will combine day-to-day accounting ownership with ERP implementation and practical uses of AI. Full professional fluency in English is essential, as you will interact confidently with international stakeholders, global business partners, and external advisors across jurisdictions.

Missions

Accounting Operations

Take ownership of the accounting function’s internalization: map all activities currently handled by external accountants and execute a phased handover covering records, opening balances, responsibilities, controls and deadlines.

Deliver a significant improvement in the quality, accuracy and consistency of the accounting records, ensuring that transactions are properly supported, classified and reflected in the general ledger.

Strengthen monthly, quarterly and annual closing schedules, documented journal entries, analytical reviews and clear explanations of material movements and variances.

Establish rigorous balance-sheet reconciliations for all significant accounts, with documented support, timely investigation of discrepancies and disciplined clearance of aged or outstanding items.

Develop a deep understanding of the accounts and underlying business flows, enabling reliable financial analysis, early identification of accounting issues and clear communication of financial performance to management.

Improve accounting policies, documentation and internal controls in line with applicable accounting standards and external reporting requirements; coordinate statutory accounts, tax filings and audit requests with external advisors while retaining clear internal ownership.

ERP implementation

Lead a significant 12-month ERP implementation project that must be delivered from requirements definition through testing, data migration, go-live and stabilization, working closely with internal teams and implementation partners.

Define the chart of accounts, analytical dimensions, accounting rules and approval workflows; connect purchasing, billing and banking processes to the ledger.

Document workflows, train users and support adoption; prioritise improvements that reduce manual work, strengthen controls and shorten the close.

Artificial Intelligence (AI)

Identify, assess and pilot high-value AI applications across accounting, including invoice and document extraction, reconciliation support, anomaly detection, close assistance, cash-flow analysis and first drafts of variance commentary.

Build controlled AI workflows using approved tools that protect confidential data; validate outputs against source records and retain clear human accountability for accounting judgments, journal entries, approvals and payments.

Define success measures for each use case and turn successful pilots into documented, scalable workflows that colleagues can use consistently.

What you bring

A degree in accounting, or an equivalent professional qualification, and at least five years of relevant accounting experience.

Hands-on ownership of general ledger accounting and month-end and year-end closes, with strong reconciliation skills and a sound command of international accounting standards and cross-border reporting requirements.

Experience working with external accountants and auditors. A background combining accounting practice and an in-house accounting role would be valuable. Experience in a SaaS environment would be an advantage.

Practical experience implementing or significantly improving an ERP, including defining requirements, testing workflows and validating migrated data.

Strong Excel skills and confidence working with accounting data. Experience with reporting tools, data integrations or workflow automation is a plus.

A structured, detail-oriented approach, with the autonomy to take work through to completion and the ability to prioritise operational deadlines alongside improvement projects.

Full professional fluency in English, with clear communication and a collaborative mindset: you can explain accounting issues to non-specialists and collaborate effectively with international stakeholders, colleagues, advisors and system partners.

What we offer

• Competitive salary: €60,000 – €65,000 gross annually, depending on experience and qualifications.
• Permanent contract (CDI) based in Paris.
• Hybrid working policy: 2 remote working days per week, subject to company policy.
• International exposure: Work closely with teams and stakeholders across Europe, North America, the Middle East and Asia-Pacific.
• A key role with real ownership: Take the lead in bringing accounting operations in-house and shaping the company's financial processes.
• High-impact projects: Drive ERP implementation, process automation and AI integration within the finance function.
• A collaborative, human-scale environment with accessible management and opportunities to make a tangible impact.
• Regular team events: Team lunches, afterworks and company initiatives.
• Dedicated onboarding programme to support your integration.
• Horizon is an equal opportunity employer. We promote diversity, multiculturalism, and inclusion.