December 1, 2023by Daniel Abib0

We had a great time attending the 2023 INFORMS Annual Meeting that took place between October 15th to October 18th in Phoenix, AZ. This is one of the largest conferences in the field of OR, with 6,000+ attendees and 1,400+ sessions.

The BAL had a strong presence at the conference with four presentations:

  • On October 15th, we had two presentations:
    • Cristián Bravo presented the work with Kamesh Korangi and Christophe Mues on “Large-Scale Portfolio Optimization using Graph Attention Networks”.


  • Daniel Abib presented the work with Cristián Bravo, Raffaella Calabrese, and María Óskarsdóttir on “Optimal Feature Split in Classification Models with Dependency”.


  • On October 17th, Sahab Zandi presented the work with Kamesh Korangi, María Óskarsdóttir, Christophe Mues, and Cristián Bravo on “Leveraging Dynamic Multilayer Networks for Modelling Credit Risk Contagion in SMEs”.


  • On October 18th, Yuhao (Jet) Zhou presented the work with Collins Ntim, María Óskarsdóttir, Matthew Davison, and Cristián Bravo on “Uncovering the Network Power Gap: A Deep Learning Approach to Investigating Gender Disparities in the Boardrooms of Canadian Public Firms”.


We also had fun trying a few good restaurants in Scottsdale, AZ!

This was a great chance to showcase the preprints that will come out in the next few months. Stay tuned for them!

October 6, 2023by Cristian0

We had a great time attending the Credit Scoring and Credit Control Conference XVIII that took place between August 30th to September 1st in Edinburgh, UK. This conference bridges the academic/practitioner divide and is the world’s premier conference for credit scoring and credit risk related topics.

The BAL had a strong presence at the conference with six presentations:

  • On August 30th, Cristián presented the work with our PhD student Mahsa Tavakoli, cosupervised by Rohitash Chandra from UNSW, on “Multi-Modal Deep Learning for Midcap Credit Rating Prediction Using Text and Numerical Data”.
  • On August 31st we had two presentations:
    • Our collaborator Prof. María Óskarsdóttir from Reykjavík University, Iceland, presented the work by our PhD students Sahab Zandi and Kamesh Korangi, cosupervised by Prof. Christophe Mues from Southampton University and Cristián, titled “Credit Scoring with Dynamic Multilayer Graph Neural Networks”.
    • Cristián presented the work led by our PhD student Sherly Alfonso Sánchez, cosupervised by Prof. Kristina Sendova here at Western, called “Causal Learning for Credit Limit Adjustment in Revolving Lending Under Adversarial Goals”.
  • On September 1st, we had three:
    • Daniel Abib, who joined earlier this year as a postdoc at the Lab, presented the work coauthored with Prof. Raffaella Calabrese for Edinburgh University, Prof. María Óskarsdóttir, and Cristián. The work was called “Optimal Feature Split in Credit Risk Models with Dependency”.
    • Our PhD student Kamesh Korangi presented the work from his PhD, coauthored with Christophe Mues and Cristián, on “Deep Temporal Graph Networks for Behavioural Scoring Prediction in Revolving Credit Lines”.
    • Our PhD student Sahab Zandi presented the work with coautored with Kamesh, and cosupervised by Prof. María Óskarsdóttir, Prof. Christophe Mues, and Cristián. These last two works are part of the collaboration with one of the largest consumer banks in the world. Sahab’s presentation is titled “Modelling Credit Risk Contagion for SMEs over Supply Chains using Dynamic Multilayer Networks”.

The conference provided a great opportunity to meet and network with people in the field of credit risk from both academia and industry. We were honestly surprised and happy with the reception that we had from the conference attendants. We had many interesting talks and we look forward to what will come out of these chats!

We also had a blast having a reunion with some friends and colleagues after a while in Edinburgh!

We would like to thank the organizers, Professor Galina Andreeva and Professor Jonathan Crook from the Credit Research Centre at the University of Edinburgh, plus of course our collaborator Prof. Christophe Mues for hosting this wonderful conference. We look forward to attending the next one in 2025!



August 15, 2023by Cristian0

I had a great time presenting a keynote and a paper at the SIGKDD 2023, one of the elite conference in computer science. In my personal opinion, the KDD is the top applied data science conference, as NeurIPS is a bit too theoretical, while the KDD is a bit more integrative. Lots of papers this year in network science and causal learning, which was encouraging when evaluating the current research lines of the group.

I presented two works in the Machine Learning in Finance workshop of the conference:

  • The keynote “Leveraging Deep Learning for Multimodal Data Analysis in Credit Risk Assessment“, where I summarized the latest work of the lab in using multimodal data for the analysis of credit risk in midcaps and retail lending. I presented results of our latest preprints (paper on midcapspaper on mortgages) and preliminary results on using LiDAR for mortgage analysis and social network analysis for credit risk modelling. I shared the stage again with three other keynotes from Bloomberg and Blackrock, the same groups that presented in the Columbia-Bloomberg seminar in May we also presented in, and with Srijan Kumar from Georgiatech. Srijan was keynote in the NeurIPS workshop we presented our paper on influencer detection (NeurIPS paper, journal preprint). The machine learning in finance world seems to be pretty small!
  • The paper “Graph Attention Networks for Portfolio Optimisation: Empirical Evidence for Mid-Caps” by our PhD student Kamesh Korangi. Kamesh couldn’t attend as the US visas are taking forever. In this talk I showed the preliminary results of our work on using GATs for optimizing portfolios. We are really excited about this work! I can’t wait to show the world about in the near future. Stand by for the preprint, it should be available in a few months. The presentation itself will be available in a few weeks, I’ll update this post when it is.

It was a fantastic experience to attend the KDD in person. Sadly, we weren’t able to do so in 2020 due to the pandemic, where we presented the preliminary results of our paper in default propagation across multilayer networks (KDD paper, YouTube video with the presentation at CORS 2021, extended journal paper). It was great to be able to present now and share with so many top researchers.

The conference was in Long Beach, so I also got to have some great weather.

Cristian in front of the sunny Long Beach Convention Center

The acceptance rate of the conference was higher than previous years, around 20%. However, the MLF workshop was even more selective with only around 10% of the papers being selected for spotlight talks! It was great to be in such an exclusive group.

Slide with the acceptance rate of the KDD conference per areas. Finance is 22%.

Also, it was great to see so many Latin Americans there! We had a few meetings and even some went salsa dancing. We were very pleased to also meet with Ricardo Baeza-Yates, a legend in the field.

Latin Americans sharing a lunch at the KDD.

Overall, it was a great experience. Hopefully we’ll be able to attend to KDD 2024 in Barcelona!

Our research focuses on using reinforcement learning (RL) to address the credit limit modification problem for companies offering credit card products. This involves two main challenges: defining the RL problem for this specific task and training the RL agent without conducting online experiments with customers.

To define the RL problem, we consider the financial history of credit card holders and the expected losses due to defaults when deciding whether to increase or maintain their credit limits. The actions available are increasing the limit or keeping it the same. We calculate the reward function based on the expected profit, considering the revolving aspect of credit card usage. This differs from previous studies that overlooked this aspect in profit calculations.

To train the RL agent offline, we use a two-stage model to simulate the balance after taking an action. This involves selecting the balance type and predicting the balance amount using a regressor model. Through our experiments, we found that our trained Double-Q learning agent outperformed other strategies, including the one used by Rappi, a Latin American fintech company known for its delivery and commerce services that has also ventured into banking with its RappiCard credit card, and that was our collaborator in this research.

Our research contributes by providing a conceptual framework for applying RL to credit limit adjustments and emphasizes data-driven decision-making rather than relying solely on expert judgments. Furthermore, we discovered that incorporating additional predictors did not improve the performance of our simulator. This implies that fintech companies do not necessarily have an advantage over traditional banking institutions in this specific task.  Figure 1  provides an overview of the proposed methodology’s general workflow.












Figure 1: Methodology’s general workflow.

Link to the working paper:

June 26, 2023by Cristian0

Always fun to be on the CBC News’ Weekend Business Panel. This week I was asked to talk about the price fixing fine on Canada Bread, Equifax’s reporting small businesses have significantly increased their credit card debt (and reduced loans), and the most livable cities ranking from The Economist.

With respect to the second point, in general it is not a good sign. It is not clear why businesses are using more revolving debt (no good reason though), but the reduction in traditional lending does reflect lower investment in the future. I think the pinch of inflation plus high cost of debt is being felt more widely already. The FT called it the “pain phase” earlier this week: the period where rates are high, but inflation still hasn’t come down.

See my thoughts below!

June 8, 2023by Cristian0

The Bank of Canada raised the interest rate once again, shocking a section of the market. I honestly expected this as the fundamentals aimed at it, with inflation still high, a tight labour market, the US still very aggressively raising rates, and the time it takes for people to renew their mortgages and take higher rates. Also, relative to inflation interest rates are still around historical averages.

It sadly does mean higher debt costs for everyone. This will also mean a slowdown in the medium term, but how big will this be (either a recession or not) is anyone’s guess. Canada has a safer banking system, so interest rate risks are significantly lower, giving more runway to the BoC for future rises.

CTV News London interviewed me about this yesterday. I speak around 6 minutes in.

May 29, 2023by Cristian0

I had the opportunity to be at CBC News‘ Power and Politics on Friday speaking about the debt ceiling. First time in a TV studio! Time went so fast I didn’t even mentioned anything about the specific impact on the stock and bonds markets of either a shutdown or a default. As there is a deal now, my second point on the specifics of the deal are more important. Any deal could impact Canada’s bottom line for years to come. So far, it seems like a general reduction in spending growth to no more than 1% yearly, rather than specific programs cut, we’ll know in the next few days. These are good news for Canada in general, at least much better than cuts that could threaten specific strategic industries.

The interview is below, I start at 29:18.

Extending the coverage, the Canadian Press interviewed me about it. The interview was then featured at The Toronto Star, here. Also, CIXXFM here in London took a bit of a different path, focusing more on the personal finance side of it (don’t panic!!). This interview can be read here.


May 20, 2023by Cristian0

I had the true honour of being invited by Prof. Ali Hirsa to present at this excellent workshop. The organizers review 1400 abstracts published during the year and select the ones that according to them reflect the most significant research at the intersection of ML and Finance. Our work with Kamesh Korangi and Christophe Mues, “A transformer-based model for default prediction in mid-cap corporate markets” [paper, ArXiV], was one of them!

Excellent roster of speakers, including people from MIT, Stanford, Blackrock, Morgan Stanley, and of course, the hosts Columbia and Bloomberg. Everything went amazing except that the IT team lost a few of my slides, but I think the audience did not mind very much. I look forward to keep engaged with such an excellent team moving forward. Here are a few pictures of the event.

Cristián on the stage before his presentation at the Alfred Lerner Hall

The presentation was at the amazing Alfred Lerner hall at Columbia University. 400 attendants from industry and academia were present.

The stage at the Alfred Lerner hall

April 24, 2023by Cristian0

Stock image of code of ethics

During 2022 I had the pleasure of participating on a series of workshops discussing the challenges in AI applied to financial institutions. I was part of a group of 30 professionals from industry and academia. The forum was organized by the Office of the Superintendent of Financial Institutions (OSFI), Canada’s prudential banking regulator. These discussions will inform the future regulation in the area that OSFI is targeting for release later in the year.

The report discusses the EDGE model for financial institutions: Ethics, Data, Governance, and Explainability. It aims to provide general guidelines to strike the right balance between regulation and innovation. I greatly enjoyed all discussions that led to this report, in my minor capacity as participant.

Give it a read in this link.

April 17, 2023by Cristian0

I was on the CBC panel again this weekend! This week we spoke about the BoC’s decision to keep the monetary policy rate steady, the Mercer report on Millennial renters needing 50% more upon retirement (not a fan of the study) and Amazon’s Bedrock & Titan, although my producer cut me off because we were running out of time. I had a lot more to say about AI!

What I didn’t say on Saturday: I believe we will end up in a three-tiered world: A first world of companies developing these models (having the technological capacities and data availability to properly train them). A second world of companies that can take outputs of these models, or available public models and fine-tune them over either private or public infrastructure (BloomberGPT for example and several research projects I am working on). And a third world of companies that will be technology takers and deploy these technologies either via live services (such as Amazon Bedrock) or via prepackaged assistants (such as LLM-powered Bing or Microsoft’s Copilot).

See the panel below.