Horizon Trading Solutions is an independent global technology company focused on electronic trading, supporting agency and principal business activities across equities and derivatives.

For over 20 years, we have equipped leading capital market participants with algorithmic trading technology and direct connectivity to more than 80 exchanges worldwide.

We are currently looking for a RSSI to strengthen our cybersecurity posture and lead the execution of our key security initiatives.

This newly created role combines security strategy with hands-on execution. You will assess our existing environment, define clear priorities and work closely with our technical teams to ensure that security improvements are effectively implemented.

Your Key Responsibilities

Identity, Access & Infrastructure Security 

• Assess and strengthen identity and access management across the organisation.
• Improve MFA, SSO, RBAC, privileged-access management and access-review processes.
• Strengthen the security of our Microsoft environment, particularly Microsoft Entra ID.
• Review the security of internal networks, endpoints, servers and cloud or on-premise environments.
• Identify security weaknesses and work with technical owners to implement remediation actions.

Cybersecurity Strategy & Roadmap

• Assess Horizon’s current cybersecurity posture and main areas of exposure.
• Define and maintain a pragmatic, risk-based cybersecurity roadmap.
• Translate identified risks into prioritised actions, owners and deadlines.
• Drive security initiatives and ensure that agreed improvements are effectively delivered.
• Track and communicate key risks, remediation progress and security priorities.

Vulnerability Management, Monitoring & Incident Response

• Establish proactive monitoring of vulnerabilities and emerging threats.
• Coordinate penetration tests and manage remediation plans through to closure.
• Improve security monitoring capabilities, including SIEM, EDR, logging and alerting.
• Define and test incident-response procedures.
• Support the investigation and coordination of cybersecurity incidents.

Cyber Resilience

• Review disaster-recovery, backup and business-continuity capabilities.
• Define and test recovery procedures for critical systems.
• Organise cyber-crisis simulations with technical and business stakeholders.
• Identify and address resilience gaps affecting business-critical services.

Security Advisory & Stakeholder Support

• Provide practical security guidance to IT, Engineering, Product and Support teams.
• Support client security reviews, audits and technical due-diligence processes.
• Present key cybersecurity risks and priorities to senior management.
• Promote pragmatic security practices aligned with operational and business constraints.

Profile

What we are looking for

• At least five years of hands-on experience in cybersecurity.
• Strong experience in identity, access, infrastructure and network security.
• Good knowledge of Microsoft security environments, particularly Microsoft Entra ID.
• Experience with vulnerability management, penetration testing, monitoring and incident response.
• Ability to define a pragmatic security roadmap and drive remediation actions through to completion.
• Autonomous, pragmatic and action-oriented mindset.
• Professional fluency in English.
• Experience with application security, DevSecOps, business-critical SaaS, financial software or electronic trading environments would be a plus.

Technical Environment

• Microsoft Entra ID and Microsoft end-user environment
• Cloud, on-premise and hybrid infrastructure
• Networks, firewalls, endpoints and servers
• SIEM, EDR, centralised logging and monitoring tools
• Java-based electronic trading platform
• Linux, Docker and CI/CD environments
• Real-time and business-critical systems

Why Join Us ?

• Take ownership of cybersecurity within an international fintech.
• Combine security strategy with concrete and visible execution.
• Work on business-critical electronic trading technology.
• Collaborate closely with experienced technical teams and senior management.
• Contribute directly to Horizon’s next stage of cybersecurity maturity.
• Join an international and human-sized organisation where your work can make a real difference.