AI Researcher, LLMs London, United Kingdom NY

London, United Kingdom;
New York, NY, United States

Hudson River Trading (HRT) is seeking an LLM-focused AI Researcher to join the HAIL team (HRT AI Labs). The LLM team builds large language models from scratch—pretraining, post‑training, and serving—deployed across the firm to accelerate research, engineering, and trading workflows.

• Tokenizer training, dataset curation and mixing, pretraining, post‑training, evaluation design, inference, and live‑trading.
• Work independently on the full model development loop with minimal bureaucracy.
• Drive frontier capability gains and ship code that achieves those gains.

• Two or more years of hands‑on experience training, post‑training, or evaluating LLMs at scale.
• Direct experience with large‑scale pretraining, post‑training (SFT, RL), LLM evaluation design and statistical analysis, or distributed training/inference systems.
• Research taste: ability to identify promising directions, design ablations that influence decisions, and update beliefs from evidence.
• Strong engineering skills valued, e.g., GPU kernel development, lower‑level PyTorch internals, or published work on frontier‑style LLM results.

The estimated base salary range is 200,000 to 300,000 USD per year (or local equivalent). Compensation is location‑dependent and may vary by factors such as job‑related knowledge, skills, and experience. The role is also eligible for discretionary performance‑based bonuses and a competitive benefits package.

HRT is an equal opportunity employer; we value and respect diversity and inclusion. We do not discriminate on the basis of any protected characteristic and comply with all applicable equal‑employment‑opportunity laws and regulations.