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JoaFin

Quantitative finance consulting

Models that hold up under scrutiny

JoaFin builds quantitative models — statistics, machine learning, risk and valuation — and the backend that puts them to work in the hands of a trading desk. We use AI heavily to move fast; what we deliver rests on mathematics we can derive, document and defend in front of a committee, a regulator or a court.

μνTxT(x)
The Monge map T pushing a mixture of densities μ onto its target ν — computed from the densities, not drawn. It is the theory used to calibrate arbitrage-free volatility surfaces, and the subject of the doctoral research this practice was built on.
T#μ=ν,T=Fν1FμT_\#\mu = \nu, \qquad T = F_\nu^{-1} \circ F_\mu

F_μ and F_ν are the distribution functions. On the line, with convex cost, the optimal map is the monotone rearrangement — which is exactly what the figure computes.

What we bring to the table

  • Statistics and machine learning

    Predictive modeling, uncertainty quantification and validation. With published research on when a learning model converges and when it does not.

  • Mathematical finance

    Derivatives, local volatility, pricing and numerical methods running in production.

  • Risk and heavy tails

    Extreme value methods, daily CVaR limits and statistical arbitrage traded on a desk.

  • Energy markets

    Locational marginal price forecasting and daily trading in the Mexican power market.

  • PhD in Mathematics

    University of Toronto, 2024, under Robert J. McCann. Analysis, probability and optimal transport.

  • Backend for quant teams

    From data acquisition to the model the desk queries every day.

The starting point

AI accelerates the work. Mathematics is what holds it up.

JoaFin exists for a specific reason: a lot of people are using AI badly. They use it to skip past framing the problem rather than to reach a well-framed one sooner. Our bet is the quantitative consulting that always worked — models, risk, valuation, infrastructure — amplified by these tools rather than replaced by them.

A quantitative model is not worth what it cost to write. It is worth what can be asserted about it: the conditions under which it converges, the assumptions it rests on, how sensitive it is to the data, and where it stops being valid.

We use language models every day to implement, review literature, prototype and automate. It is a genuine speed advantage and we take it without apology. But problem formulation, choice of method, error bounds and verification are ours, and they are not delegated.

On this we are not speaking second-hand. One chapter of the doctoral thesis this practice is founded on is precisely about when a machine learning model converges under modification of its data, and when it does not. The proof is published. We know where these tools break because that was the object of study.

The practical consequence: you get in weeks what traditionally takes months, without giving up traceability of a single assumption.

How we work

Services

Seven distinct areas, one criterion: the method is chosen for what can be proven about it.

  • 01

    Statistics and machine learning

    Predictive models built to be valid, not merely to fit well in sample. This is the area where apparent performance is most often mistaken for real performance.

  • 02

    Mathematical finance and derivatives

    Pricing, calibration and numerical methods for volatility surfaces and nonlinear structures. This is day-to-day work on the team.

  • 03

    Risk, heavy tails and statistical arbitrage

    Risk measurement where Gaussian assumptions fail — which is precisely where risk matters.

  • 04

    Power and energy markets

    Nodal price, demand and risk models for participants in the Mexican power market and international counterparties.

  • 05

    Data, backend and productization

    Most of the work ends up here: the model has to run on its own and sit within reach of whoever decides.

  • 06

    Actuarial modeling

    Valuation of contingent liabilities, decrement tables and stochastic projections with explicit assumptions.

Have a problem that spreadsheets won't settle?

If the problem is quantitative, ill-posed or simply hard, the first conversation usually clarifies more than expected. No cost, no obligation.