We are looking for an experienced Financial Systems Specialist with deep technical expertise in OneStream to join our Global Financial Systems team. Working across global platforms and solutions, you will take technical ownership of OneStream, our new group consolidation platform, transitioning ownership from the implementation partner. You will be hands-on in configuring, developing and optimizing the platform, supporting its ongoing operation across consolidation and tax, leading the Phase 2 rollout and shaping the future roadmap.  OneStream is the starting point, not the boundary. Beyond establishing ownership of the platform, you will have the opportunity to expand into other global financial systems and broader Finance Technology initiatives, leveraging automation and AI to enhance existing workflows, streamline processes and drive operational efficiency.    What you'll do  • Own and develop the OneStream platform end-to-end, including configuration, metadata, hierarchies, business rules, workflows, integrations and security, ensuring a stable, scalable and well-governed platform.  • Lead the Phase 2 rollout across Finance and Tax, partnering closely with Group Finance and Tax to shape the platform roadmap, while working with regional finance teams to understand their requirements and deliver effective technical solutions.  • Transition ownership from the implementation partner, building internal expertise, reducing reliance on external support and managing vendor relationships, releases and upgrades.  • Drive platform design and integration, assessing the upstream and downstream impact of changes across NetSuite, source systems and reporting solutions.  • Own platform support and continuous improvement, including period-close support, incident management and root cause analysis, leveraging automation and AI tooling to streamline workflows and eliminate manual processes.  • Build and share technical knowledge, maintaining clear documentation, mentoring colleagues and strengthening platform capability across the global team.  • Expand into broader Finance Technology initiatives, taking on additional global platforms and contributing to scalable, consistent solutions across regions.    Who you are • Hands-on OneStream expertise, with at least 3 years of experience in platform administration, ownership or implementation, covering metadata, hierarchies, business rules, workflows and the close cycle.  • Broader financial systems experience, with 4–6 years in financial systems, finance transformation or CPM consulting, including experience with other enterprise platforms such as NetSuite, Workday or Coupa.  • Strong technical capabilities, including SQL, data modelling, scripting, APIs, integration tooling and version control, alongside an understanding of SaaS security, access controls and audit requirements.  • Proven implementation experience, having delivered or played a significant role in a OneStream implementation or major rollout phase.  • Understanding of financial processes, particularly group consolidation and the financial close cycle. Exposure to tax provisioning and OneStream's BDO module is a plus.  • A continuous improvement mindset, with practical experience using automation and AI to improve workflows, reduce manual work and deliver measurable efficiencies.  • An ownership mindset and strong communication skills, with the ability to work independently, exercise sound judgement and translate complex technical concepts into clear business language for finance stakeholders.  • A collaborative, growth-oriented approach, with an interest in expanding beyond OneStream into the wider financial systems landscape, sharing knowledge and maintaining clear technical documentation.    Who we are At Optiver, our mission is to constantly improve the market by injecting liquidity, providing accurate pricing, increasing transparency and acting as a stabilizing force no matter the market conditions. With a focus on continuous improvement, we participate in the safeguarding of healthy and efficient markets for everyone who participates. As one of the largest market making institutions, we are a trusted partner of 70+ exchanges across the globe.   What you'll get You’ll join a culture of collaboration and excellence, where you’ll be surrounded by curious thinkers and creative problem solvers. Motivated by a passion for continuous improvement, you’ll thrive in a supportive, high-performing environment alongside talented colleagues, working collectively to tackle the toughest problems in the financial markets. In addition, you’ll receive: • A performance-based bonus structure unmatched anywhere in the industry. We combine our profits across desks, teams and offices into a global profit pool. • The opportunity to work alongside best-in-class professionals from over 50 different countries. • 25 paid vacation days in your first year, increasing to 30 from your second year onwards. • Training opportunities, discounts on health insurance, and fully paid first-class commuting expenses. • Extensive office perks, including breakfast, lunch and dinner, world-class barista coffee, in-house physio and chair massages, organized sports and leisure activities, and Friday afternoon drinks. • Training and continuous learning opportunities, including access to conferences and tech events. • Competitive relocation packages and visa sponsorship where necessary for expats.   How to apply Apply directly via the form below. If you have any questions feel free to contact our Recruitment team via our recruitment inquiry form. Please note: • We do not require any assistance from third-parties including agencies in the recruitment of this role • We cannot accept applications via email   Diversity statement Optiver is committed to diversity and inclusion.