Senior Data Scientist - Credit Risk Modelling

The Credit Risk Modelling team owns credit risk and Customer Lifetime Value (CLtV) modelling for iwoca's UK and German lending. That covers the probabilistic machine learning models behind every credit decision, plus the CLtV models that shape pricing and portfolio strategy.

The team is around twelve data scientists. Some work on auto-space models that decide within five minutes from data candidates authorise us to pull. Others work on manual-space models that pick up when a credit analyst adds digital footprint and income data, which lands a decision within 24 hours.

• Domain experience. You've worked in credit risk, lending, or customer lifetime value modelling.
• Coaching. You've helped other data scientists improve their work, through review or mentoring.
• Non-linear methods. You can think in terms of the cost function and inductive biases of your models.
• Bayesian methods. You've used hierarchical models, MCMC, or Bayesian updating in real work.
• Time series modelling. You've modelled temporal data where autocorrelation, drift, or seasonality mattered.
• Coding. You can write code for analysis. The team works in Python.

The salary

We expect to pay from £90,000 – £130,000 for this role. But, we’re open-minded, so definitely include your salary goals with your application. We routinely benchmark salaries against market rates, and run quarterly performance and salary reviews.

The culture

At iwoca, the best idea wins. We model our culture on independent thinking, challenging untested logic, and evidence-based decisions. We prioritise learning and growth, and give people the autonomy to develop in the direction that makes them most effective.

We're a tech company and believe in the power of AI to help us work faster and better. We provide the infrastructure where every iwocan always has access to the best models and where those models have access to all of our data. We will help our people to learn how to use and grow with the new tools available to them.

The offices

We put a lot of effort into making iwoca a great place to work

• Offices in London, Leeds, Berlin, and Frankfurt with plenty of drinks and snacks.
• Events and community-led groups, including running groups, padel, and monthly ping-pong and pool competitions.

• Causal estimation of offer terms. Estimating the causal effect of amount, duration, and price on customer outcomes.
• Unifying automated and manual models. Finding a principled way to put the two model families, which optimise slightly different objectives, on a common cost function.
• IFRS accounting model. Developing a multi-stage model where recovery predictions feed back to improve the upfront loss estimates that International Financial Reporting Standards (IFRS) require.
• Generalising credit and CLtV. Exploring whether a single, more general model could replace the separate credit and CLtV models.

The requirements

• Applied statistics. You have a background in statistics from a quantitative field – typically a degree or Master's in Statistics, Mathematics, Physics, or similar. You've applied it to commercial problems for several years, and chosen the methods yourself. You know when the data breaks a method's assumptions, and what that does to your answer.
• Probabilistic reasoning. You quantify the uncertainty in each estimate, and treat calibration as a first-order concern.
• Production ML. You've built supervised ML models end to end – exploration, training, deployment, and monitoring.
• Judgement. You critically evaluate model output – yours, a colleague's, or an LLM's – and can explain why a choice is right. You defend your reasoning under challenge, and challenge others' when the evidence points elsewhere.
• Project leadership. You've led modelling projects you spotted yourself, from framing the question to a decision the business acted on. Some of that work changed how a team models a problem.
• AI leverage. You've used AI to produce work you couldn't have delivered without it, and built tools or workflows your colleagues now use. You judge where it helps and where it doesn't.
• Communication. You write and speak clearly, directly, and concisely. You adapt technical detail to your audience.

• Flexible working hours.
• Medical insurance from Vitality, including discounted gym membership.
• A private GP service (separate from Vitality) for you, your partner, and your dependents.
• 25 days’ holiday per year, an extra day off for your birthday, the option to buy or sell an additional five days of annual leave, and unlimited unpaid leave.
• A one-month, fully paid sabbatical after four years.
• Instant access to external counselling and therapy sessions for team members that need emotional or mental health support.
• 3% Pension contributions on total earnings.
• An employee equity incentive scheme.
• Generous parental leave and a nursery tax benefit scheme to help you save money.
• Electric car scheme and cycle to work scheme.
• Two company retreats a year: we’ve been to France, Italy, Spain, and further afield.

• A learning and development budget for everyone.
• Company-wide talks with internal and external speakers.
• Access to learning platforms like Treehouse.

• iwoca benefits & policies https://coda.io/@iwocauk/iwoca-benefits-policies-uk
• Interview welcome pack https://coda.io/@iwocauk/interview-welcome-pack-tap