Sebastian Kaczmarczyk-Alternative Data Analyst/Decision Scientist
Check rate
Experience
Alternative Data Analyst/Decision Scientist
Balyasny Asset Management
- Led the development of three internal data/AI products for Portfolio Manager teams, created PoCs, defined requirements, and coordinated engineering to deliver production-ready tools.
- Owned relationships with hundreds of internal stakeholders, ensuring efficient data access, clear prioritization, and smooth collaboration across Tech, Data, and PM teams.
- Managed a 7-person engineering team, overseeing sprint planning, resource allocation, and workflow optimization to remove bottlenecks.
- Built several AI-driven utilities to enhance internal research and data handling efficiency.
Senior Data Scientist
J.P. Morgan Chase
- Worked closely with Marketing, Customer Experience, and Finance to turn business problems into clear technical requirements.
- Delivered a customer experience chatbot using modern NLP/LLM approaches, improving internal support workflows.
- Built multiple data-driven tools and analyses supporting European business units.
- Collaborated with cross-functional partners to clarify needs, validate assumptions, and deploy solutions into day-to-day use.
Senior Data Analyst
RTB House
- Reduced Account Manager analysis workload by ~25% through process automation and improved reporting.
- Designed an internal forecasting tool and built dashboards used across APAC stakeholders.
- Led a project using NLP on customer audio/video interactions to flag churn risks, guiding AM teams toward retention opportunities.
- Enhanced operational efficiency through systematic reporting and tool development.
Business Analyst
Bain
- Supported due diligence projects and operational improvements for clients.
- Worked on UI/UX optimization and A/B testing initiatives.
- Conducted analysis across customer behavior, segmentation, and product performance.
Investment Analyst
Sunfish Partners
- Conducted in-depth fundamental analysis of potential investments.
- Tracked and managed deal flow pipeline.
- Developed and implemented marketing strategies to enhance brand awareness, attract potential customers or investors, and increase market share.
Funding Consultant
Grantland
- Performed market and business-side analytics.
- Led the development of comprehensive business plans, including defining business objectives, target markets, competitive strategies, and financial projections.
Industry experience
See where this freelancer has spent most of their professional time.
Experienced in Banking and Finance, Professional Services, Advertising, and Information Technology.
Business area experience
See which departments and functions this freelancer has contributed to most.
Experienced in Business Intelligence, Product Development, Project Management, Customer Service, Information Technology, and Operations.
Summary
AI & data product leader with experience delivering products end-to-end in high-stakes financial environments. I combine technical understanding (LLMs, data pipelines, alt-data, cloud) with strong product ownership, cross-functional communication, and team leadership.
I’ve managed engineering teams, gathered requirements from senior investment professionals, built PoCs, and driven products from concept to production — improving workflows, reducing operational bottlenecks, and enabling revenue-generating insights.
I bring a mix that’s hard to find: I understand the technical side well enough to build prototypes and guide engineers, but I also think like an operator who cares about adoption, deadlines, and real impact. I’ve already shipped AI/data products in complex financial environments, managed teams, and worked with demanding stakeholders. I know how to turn a vague idea into a working solution, and I take full ownership from the first discussion to the moment a tool is actually used. If you need someone who can deliver fast, communicate clearly, and raise the bar for how product is run — that’s what I do best.
Skills
Core Skills
- Product Ownership & Delivery
- Stakeholder Management
- Requirements Gathering
- Team Leadership
- Ai/Llm Product Development
- Data Products
- Operational Efficiency
- Cloud (Aws / Gcp)
- Sql
- Python
Tech Skills
- Python
- Git
- Data Pipelines & Automation
- Dashboarding (Tableau/ Looker)
- Llms & Nlp
Languages
Education
Polish-Japanase Institute of Information Technology
MSc in Data Science · Data Science · Warsaw, Poland · 4.7/5
Warsaw School of Economics (SGH)
MSc in Finance and Accounting · Finance and Accounting · Warsaw, Poland · 4.6/5
The University of Sheffield
LLB Law · Law · Sheffield, United Kingdom · 1st Class Honours Degree
Statistics
Experience
Expertise
Qualifications
Profile
Frequently asked questions
Have questions? Find more information here.
Sebastian is based in Warsaw, Poland.
Sebastian speaks the following languages: Polish (Native), English (Advanced), Spanish (Intermediate).
Sebastian has at least 8 years of experience. During this time, Sebastian has worked in at least 6 different roles and for 6 different companies. The average length of individual experience is 1 year and 3 months. Note that Sebastian may not have shared all experience and actually has more experience.
Based on recent experience, Sebastian would be well-suited for roles such as: Alternative Data Analyst/Decision Scientist, Senior Data Scientist, Senior Data Analyst.
Sebastian's most recent position is Alternative Data Analyst/Decision Scientist at Balyasny Asset Management.
In recent years, Sebastian has worked for Balyasny Asset Management, J.P. Morgan Chase, RTB House, Bain, and Sunfish Partners.
Sebastian is most experienced in industries like Banking and Finance, Professional Services, and Advertising. Sebastian also has some experience in Information Technology.
Sebastian is most experienced in business areas like Business Intelligence, Product Development, and Project Management. Sebastian also has some experience in Customer Service, Information Technology, and Operations.
Sebastian has recently worked in industries like Banking and Finance, Advertising, and Information Technology.
Sebastian has recently worked in business areas like Business Intelligence, Product Development, and Project Management.
Sebastian holds a Master in Data Science from Polish-Japanase Institute of Information Technology, a Master in Finance and Accounting from Warsaw School of Economics (SGH) and a Bachelor in Law from The University of Sheffield.
The availability of Sebastian needs to be confirmed.
Daily rate distribution
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Average rates for similar positions
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The average daily rate is the mean of all daily rates from recent contracts of comparable freelancers on our platform.
The median daily rate is the middle value of all daily rates — half of comparable freelancers charge less, half charge more. Unlike the average, it is barely affected by outliers.
Calculated based on our freelancers’ daily rates as of 7 Sep 2026. Actual rates may vary depending on seniority level, experience, skill specialization, project complexity, and engagement length.
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