Financial Modelling Engineer (Python)

Job title: Financial Modelling Engineer (Python)

Salary: £70,000 - £80,000

Hybrid Working: Min 2x days a week in our London (Soho) office.

About Y TREE

We are a rapidly growing WealthTech business that is re-defining how individuals and families connect and engage with their money. We provide our clients with control over their personal finances, enhancing their ability to achieve their financial and life aspirations.

We are harnessing sophisticated portfolio analytics, innovative behavioural psychology and cutting-edge UX/UI to create a revolutionary experience and transformational outcomes for our users. The business was founded in 2017 by three successful entrepreneurs and business-builders with diverse experiences and skill-sets in Technology, Corporate Advice and Investment Management and is backed by some of Europe’s leading investors.

Team Overview

The Financial Modelling Team brings intellectual rigour to our service, focusing on what truly matters in our clients’ financial lives. We distill complex financial realities into user-friendly, actionable, and personalised insights powered by data. Every model and tool we build is designed to be robust, scalable, and purposeful, providing the unifying logic that powers the entire client lifecycle.

The Financial Modelling Engineer is responsible for the technical execution and maintenance of Y TREE’s Asset Liability Management (ALM) driven financial planning engines. Reporting to the Head of Financial Modelling , you will support the development and migration of legacy Excel models to a robust, production-grade coded system environment. You are not just running financial analyses like traditional institutions - this is a unique opportunity to write the codebase, test suites, and unifying logic that power Y TREE’s Asset Liability Management engine for high-net-worth clients.

The Role

• Execute Client Analysis: Run complex Financial Planning Analysis and ALM projections for client portfolios. Translate specific client scenarios (e.g., liquidity events, estate planning, gifting) into model inputs and generate accurate outputs for the Advice team.
• Model Development & Migration: Support the transition of the core ALM and Financial Planning Life Analysis models from legacy Excel spreadsheets to a robust, code-based environment (Python/Proprietary Stack).
• Operational Efficiency: Work to reduce the time-cost of manual analysis. Take ownership of the recurring ancillary analysis & tools, ensuring delivery within agreed SLAs.
• Data Prep & Validation: Act as the gatekeeper for data entering the financial models. Clean, format, and validate client financial data to ensure the advice we give is based on accurate inputs.
• Coding & Scripting: Write clean, efficient Python scripts to automate repetitive modelling tasks (e.g., cash flow projections, tax wrappers).
• Testing: Build and run unit tests for new model features. Compare "Excel vs. Code" outputs to ensure zero discrepancies during the migration process.
• Documentation & QA: Maintain comprehensive technical documentation for all financial models. Ensure that every assumption, tax rule, and growth factor used in the ALM is recorded and accessible to reduce key-person risk. Perform rigorous quality assurance on model outputs before they reach the Client Team. Investigate and resolve calculation discrepancies immediately.
• Advisory Support: Serve as the technical helpdesk for the Client/Advice teams regarding model outputs. Explain why the model produced a specific number and help troubleshoot "unusual" results.
• Product Implementation: Support the integration of financial models into the Y TREE digital platform by providing test cases and validating the data shown in the UI.

About You

Technical Skills

• Experience: Typically 2–4 years experience in Quantitative WealthTech, Financial Modelling, ALM Development, or Risk Analytics (focused on personal balance sheets rather than pure institutional portfolio management).
• Qualifications: Degree in finance, economics, mathematics, or a related discipline; a Master’s degree
• Technical Skills: Hands-on experience writing clean, production-grade Python scripts, modular structures, and automated tests. Crucially, you must deeply understand the underlying financial planning and general investment inputs and outputs of your models (e.g., compounding mechanics, cash flows, tax wrapper impact) - we are looking for someone who understands what the code is doing mathematically

Personal Characteristics

• Analytical & Communication Skills: Strong analytical mindset, with the ability to translate intricate code logic and mathematical outputs into clear narratives for advisers and clients.
• Mindset & Values: Curious, detail-oriented, collaborative, and aligned with Y TREE’s philosophy of intelligent, data-driven, and purpose-led investing.

What's in it for you?

• Once eligible, you'll be able to enroll onto our private healthcare plan through Vitality. This includes perks like 50% off premium gym memberships and access to their exclusive rewards programme.
• Support for your mental health and wellbeing through our employee assistance programme.
• 25 days of annual leave per year. This is 25 days each year where we expect you to turn your phone off and switch off; we would never ask you to book leave for a doctor's appointment or to see your children's school plays.
• Regular team socials to help you switch off from work and get to know your colleagues in an environment away from your desk. We ensure socials are well-balanced and offer a variety of activities to suit different needs so you always feel welcome.
• A welcoming, dog-friendly London office with appropriate spaces to cater for those with varying needs in the form of various breakout spaces and silent booths.
• As well as, a range of family-friendly policies, support towards professional qualifications, electric car schemes and more!

Our mission at Y TREE is to build diversity in our teams; diversity of thought, culture, backgrounds and perspectives. Please come as you are and let us know if there are any reasonable adjustments we can make to support you in your application process. Additionally, if you don't feel you meet 100% of the requirements please apply anyway if you feel you can demonstrate your suitability to the role. Please note, that sponsorship is not available for this role.