Mark Nyfeler holds an MSc in Mathematics from ETH Zurich, specialising in probability theory, statistics, and financial mathematics. Mark wrote his diploma thesis in collaboration with a Credit Portfolio Management Team at UBS, which is where he started his professional career in 2000. After working for five years at the UBS Investment Bank headquarters in Stamford in the US and spending a decade in the field of credit risk modelling, he gradually transitioned from credit to market risk, where he last served at UBS as Head of Market Risk Models within Group Risk Control. In this position, he led a team of around 70 people across five locations and was responsible for the design, implementation, and maintenance of UBS's Value-at-Risk (VaR) and issuer risk models for the bank's global trading portfolio.

Mark played a central role in developing the Internal Models Approach and Standardised Approach calculators for the Fundamental Review of the Trading Book (FRTB), representing UBS in discussions with the International Swaps and Derivatives Association (ISDA) and the Basel Committee on Banking Supervision (BCBS), and managing regulatory relationships with FINMA and the Federal Reserve Bank of New York. He also led the integration of Credit Suisse's market risk modelling teams into UBS following the 2023 merger. Earlier in his career, he developed credit portfolio and stress loss models, including the Credit Exposure Backtesting Framework that supported UBS's Basel II Internal Model Method approval from FINMA and the UK's Prudential Regulation Authority.