WHO WE ARE Optiver is a tech-driven trading firm and leading global market maker. For over 35 years, Optiver has been improving financial markets worldwide, making them more transparent and efficient for all participants. With more than 1,400 employees in offices around the world, we’re united in our commitment to improving the market through competitive pricing, execution and thorough risk management. By providing liquidity on multiple exchanges across the world, we actively trade on 70+ exchanges, where we’re trusted to always provide accurate buy and sell pricing – no matter the market conditions. WHAT YOU'LL DO Operating in 70+ exchanges around the world, we are building our Security team to take control of our cybersecurity and help our business stay ahead of emerging threats across our offices. As a Windows Security Engineer, you will join our global security team in our fast-paced Sydney office to help protect our data, infrastructure, and operations. You will get the chance to take ownership of our cybersecurity controls to ensure our defence always remains up to the task. You will have the opportunity to combine your knowledge of IT infrastructure, project management and a problem-solving mindset to solve business issues and independently work on improvement opportunities. This is a highly collaborative position, you will be involved in a variety of tasks such as security operations and engineering, risk analysis and security governance. Other responsibilities include: Develop and use monitoring tools to protect our systems, as well as perform security incident response and remediation when an issue is found. Take ownership of operational issues, as well as project-based work, where you will act as a lead engineer to deliver from conception through to completion. Work on security-related user requests and serve as point of escalation for the user support team. Be part of a flexible rotating on-call roster to support our global operation. WHO YOU ARE Optiver needs our next Windows Security Engineer to be someone with: 5+ years of experience working in a Windows Infrastructure Engineering role or Security Engineering specific role with background in Windows. An interest in cybersecurity events and research, with a strong engineering instinct and a deep understanding of both technical and business problems. Automation scripting experience in Python or PowerShell. Experience with Microsoft Infrastructure such as Active Directory, PKI, DNS, GPOs. Experience in securing Windows platforms, servers, and desktops such as managing firewalls, disk encryption, auditing, monitoring and event logging. Exposure to endpoint security controls such as AV, EDR, Vulnerability Scanning and Patch Management. Knowledge in common OS attack vectors, system hardening, and secure privilege escalation. Experience delivering projects end to end individually and in a team environment, from initiation to implementation. WHAT YOU'LL GET The chance to work alongside diverse, intelligent, and driven peers in a rewarding environment. We offer competitive remuneration, including: an attractive bonus structure and additional leave entitlements. Training, mentorship, and personal development opportunities. Gym membership plus weekly chair massages. Daily breakfast, lunch and an in-house barista. Regular social events including an annual company trip. A work-from-home allowance and support. Guided relocation, a competitive relocation package and visa sponsorship where necessary. As an intentionally flat organisation, we believe that great ideas and impact can come from everyone. We are passionate about empowering individuals and creating diverse teams that thrive. Every person at Optiver should feel included, valued, and respected, because we believe our best work is done together. Our commitment to diversity and inclusion is hardwired through every stage of our hiring process. We encourage applications from candidates from all backgrounds, and we welcome requests for reasonable adjustments during the process to ensure that you can best demonstrate your abilities.