About the PositionWe are looking for an industry wide Senior Subject Matter Expert (SME) – Infrastructure who can provide leadership and direction for Change-The-Bank (CTB) electronic trading infrastructure initiatives covering all technologies (in this specific domain) for Compute, Accelerators, Performance Tuning and HPC. The role sits within Citi’s Global Markets: High Performance Architectures – Infrastructure (HPAi) group.  This team is responsible for all electronic trading infrastructure architecture across all markets globally for the firm.  It is composed of low latency Subject Matter Experts (North America, EMEA), Systems Architects (both regional and asset class aligned) and an aligned initiative management function (e.g. Technical Project Manager).   Technology is key to our business; this role will require you to drive innovation and technology adoption in a large multi-faceted and complex environment.  This ICG-Tech “Subject Matter Expert” resource will collaborate with ICG-Markets “the business”, CTI “Enterprise Infrastructure”, and CISO “Security” teams driving technical architecture and engineering of CTB and End of Vendor Support (EoVS) initiatives where we choose to innovate.Reporting to the head of HPAi, the Compute, Accelerators, Performance Tuning, HPC SME will be responsible for ensuring best in breed Linux and surrounding technology architecture and engineering in alignment with business requirements.  This will be done in collaboration with CISO and CTI Compute resources aligned to HPAi who represent Enterprise and CISO priorities and standards.  Active collaboration with all parties is required to be successful.  The resource should be an industry thought leader, and able to not only steer the direction of Compute technologies for electronic trading but also roll their sleeves up and work as an individual contributor.  The resource will leverage the full strength of the supporting non-ICG technology organizations (dedicated and non-dedicated to HPAi).  The role is very broad requiring a resource that is not afraid to do new things and be challenged on a regular basis.Low Latency Trading –Markets, domain specific technology is required in (solid knowledge for as many of the following as possible with focus on Compute, HPC File Systems, Interconnects, HW and related technologies: The Technologies:<ul><li>Compute (Linux, CoreOS, Tuning, kernel bypass technologies, core dump analysis)</li><li>Network (R&amp;S, cut-through, Multicast, SDN, BGP, L1-L3, PCAP analysis)</li><li>HPC File Systems (Lustre, GPFS, Weka, DDN, Ceph)</li><li>Interconnects (InfiniBand, Slingshot, PCIe, NVLink, UALink, UPI, RoCE)</li><li>HW (Server, FPGA, GPU, Memory, Cache, over clocking, cooling, ASIC, Quantum, NUMA)</li><li>DevOps (OpenShift, Kubernetes, DevOps, Prog[Python, Perl, Shell], CI/CD)</li><li>Programming (C, C++, Java, Rust, VHDL, Verilog)</li><li>Time Sync (PTP, NTP, GPS, White Rabbit, SyncE)</li><li>Wave (RF, Millimeter, Microwave, DWDM, Photonics)</li><li>Storage (I/O, NAS, SAN, Object Store, SDS)</li><li>Database (relational, columnar, graph, NoSQL, architecture, tuning)</li><li>Monitoring (SPANs, TAPS, OEO, Packet Brokers, Corvil, SNMP, FIX, Logs, ELK, Open Telemetry, Grafana, Promethius)</li><li>Messaging (TibRV, Solace, Aeron, ZeroMQ, Kafka, Multicast, Market data (TCP/UDP), Tibco, Exegy/Vela)</li><li>Load Balancers (HW, SW)</li><li>Security (Firewalls, PKI, TLS, IDS, Optical Encryption, AD, LDAP)</li><li>Connectivity (WAN, Lucera, cross-connects, ECX, venue, client)</li><li>Colo / Datacenter (Power, Space, Cage, Rack, Cabinet, Design)</li></ul>The Skills:<ul><li>Deep knowledge of operating system fundamentals – hyper focus on Linux (REL, CoreOS) </li><li>Understanding of OSI model and TCP and UDP network protocols</li><li>Experience with Python and data libraries</li><li>Fluency with the Unix command line and shell scripting</li><li>Practical experience with modern Linux systems and systems programming concepts like C, IPC mechanisms, virtual memory, and process life cycle</li><li>Strong troubleshooting skills and knowledge of profiling/debugging tools such as gdb, perf, DTrace, SystemTap</li><li>Can understand, interpret, and improve application performance via system tuning</li><li>Thorough understanding of modern computer architecture - modern x86 AMD and Intel cache hierarchies as an example.</li><li>Kernel-bypass technology knowledge (such as Solarflare OpenOnload / TCPDirect / ef_vi, RoCE, DPDK)</li><li>Prior experience in a similar Site Reliability Engineering (SRE), DevOps, distributed computing, systems engineering/administration</li><li>Ability to context switch to work on several projects at once</li><li>Knowledge of JIRA, SCRUM, Sprints</li></ul>Details: <ul><li>Ingress/plan/execute/manage technical initiatives to make our electronic trading systems faster, more adaptable stable and maintainable aligned to HPAi standards.</li><li>Communicate ideas, requirements, and results across disparate teams.</li><li>This position will support technical populations (Rates), partnering with leaders to understand their challenges and design and execute solutions to solve them.</li><li>Communicating business and IT requirements to external vendors and internal technical teams</li><li>To succeed in this role, you must enjoy working independently and collaborating, being a hands-on contributor, learning on the fly and embrace change – rapid pace.</li><li>You must be able to understand full-stack electronic trading technologies and engage effectively in a very technical manner with other SMEs, systems architects, the business (at times), Markets-Tech, and enterprise infrastructure organizations (CTI/CISO).</li></ul>The Profile:<ul><li>Ability to efficiently analyze and deconstruct technical problems</li><li>Excellent judgment with attention to detail and accuracy</li><li>Strategic thinker who can understand and anticipate needs at all levels</li><li>You enjoy tinkering with technology in your spare time</li><li>Ability to manage time efficiently</li><li>Can work independently and as a team player</li><li>Passionate about making processes simpler and more effective, and constantly strive to make the people around them better</li><li>Strong ability to build relationships as a trusted partner, and experience coaching more junior technical resources</li><li>You are resourceful, have a sense of urgency, and are motivated to make things better and to always be learning. You don’t only want to just get the job done; you always want to deliver the highest quality work. </li><li>Strong written and verbal communication skills with strong attention to detail </li><li>Able to comprehend the major fundamentals of any project to understand how your role fits into the bigger picture </li><li>Reliable, courteous, and a flexible team player</li><li>Describes detailed problems with brevity and accuracy</li><li>Can work autonomously with strong organizational skills</li><li>Handles competing priorities in a challenging, fast-paced environment</li><li>Fluency in English required</li></ul>------------------------------------------------------Job Family Group: Technology------------------------------------------------------Job Family:Infrastructure------------------------------------------------------Time Type:Full time------------------------------------------------------Primary Location:Jersey City New Jersey United States------------------------------------------------------Primary Location Full Time Salary Range:$176,720.00 - $265,080.00 In addition to salary, Citi’s offerings may also include, for eligible employees, discretionary and formulaic incentive and retention awards. Citi offers competitive employee benefits, including: medical, dental &amp; vision coverage; 401(k); life, accident, and disability insurance; and wellness programs. Citi also offers paid time off packages, including planned time off (vacation), unplanned time off (sick leave), and paid holidays. For additional information regarding Citi employee benefits, please visit citibenefits.com. Available offerings may vary by jurisdiction, job level, and date of hire.------------------------------------------------------Most Relevant Skills Please see the requirements listed above.------------------------------------------------------Other Relevant Skills For complementary skills, please see above and/or contact the recruiter.------------------------------------------------------Anticipated Posting Close Date:Nov 15, 2025------------------------------------------------------Citi is an equal opportunity employer, and qualified candidates will receive consideration without regard to their race, color, religion, sex, sexual orientation, gender identity, national origin, disability, status as a protected veteran, or any other characteristic protected by law. If you are a person with a disability and need a reasonable accommodation to use our search tools and/or apply for a career opportunity review <a href="https://www.citigroup.com/citi/accessibility/application-accessibility.htm" target="_blank">Accessibility at Citi</a>. View Citi’s <a href="https://www.citigroup.com/global/eeo-aa-policy" target="_blank">EEO Policy Statement</a> and the <a href="https://www.eeoc.gov/sites/default/files/2023-06/22-088_EEOC_KnowYourRights6.12ScreenRdr.pdf" target="_blank">Know Your Rights</a> poster.