About me

man filming on beach

I have spent the last 12 years working on credit risk and machine learning models inside major European banks. The work has two sides: building the models (IRB PD/LGD/EAD, IFRS 9 expected credit loss, stress testing and scenario analysis), and auditing how they are used and whether they hold up to scrutiny from developers, model validators and senior risk managers. A recent piece I am proud of is a climate risk credit model for mortgage portfolios, in a domain where the methodology was still being figured out.

Alongside the day job, I like guiding people and sharing my experience. Banking regulation, machine learning techniques and their combinations are full of useful ideas trapped behind dense documents and unclear notation for readers who are not pure quants, and I enjoy the work of pulling them out and explaining them in plain language. That is what my Notes try to do, one concept at a time. I am still learning how to do this well, and I am grateful to the readers who push back when something is not clear.

Away from the desk, I cycle. I raced at a competitive level for several years, and that period taught me more about discipline than any office has: the daily training on days you do not want to get dressed and go out, and the patience of watching small improvements add up over months.

This is what cycling has taught me: a clear goal, pursued patiently day after day, almost always pays back.

Projects

Projects

Projects

Publication: Student-like models for risky asset with dependence

Journal: Stochastic Analysis and Application, Dec 1, 2016

Black-Scholes-Merton assumes Gaussian returns. Empirical asset returns are heavy-tailed, and the gap matters most in option pricing. This paper builds a class of stochastic models with exact Student-t marginals and a tractable cross-asset dependence structure, and derives a closed-form option pricing formula that improves on Black-Scholes-Merton in heavy-tailed regimes.

Go to the paper

Guest speaker, "Meet Your Future" — Alumni Università di Padova, 15 May 2017

I was invited by Alumni Università di Padova to speak in the "Meet Your Future" series at the Department of Mathematics. I shared my path from a Mathematics degree at Padova to a Risk Management role. I spoke about what a Mathematics degree gives you beyond technical content, in particular the way of thinking and the readiness to keep filling gaps in economics and finance once the work begins. The reason for accepting the invitation was simple: give back to the university that trained me and offer the next generation something helpful to use as they shape their own future in a fast-moving job market.

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Contact me

Send a message with your context. I respond to all serious enquiries.

Or write directly: francesco.castels@gmail.com

Contact me

Send a message with your context. I respond to all serious enquiries.

Or write directly: francesco.castels@gmail.com