Handling billions in portfolio calculations with a fractional team
When an investment firm's lead engineer departed, they needed a partner to maintain and enhance their proprietary composite returns calculator. Quarry stepped in as their external product and technology department, ensuring continuity, and accelerating development velocity while reducing costs.Igor / Puneet / Dennish / Senior Fullstack Engineer Maria /





Photo by Christopher Burns on Unsplash
The Challenge
The client had developed a sophisticated FinTech application for calculating composite returns – a critical method for measuring performance across multiple investment portfolios.
The product represented years of development and encoded their proprietary IP around composite analysis, transforming what had previously been managed through complex Excel spreadsheets into efficient software.
When their sole full-time engineer, who had built the product from the ground up over several years, departed for a new position, the firm faced a critical gap.
They needed a partner who could maintain this complex system and continue progress on their product roadmap. The challenge was particularly difficult given the sprawling complexity of composite calculation logic and the proprietary nature of their specific implementation.
The Solution
Rather than rushing to hire a replacement full-time engineer, the firm partnered with Quarry as their external product and technology department – a fractional resource. Our team quickly got up to speed on their proprietary composite calculation methodologies and the existing codebase.
We took over maintenance of the core platform and development of new features. The product’s complexity required deep understanding of financial composites – which provide statistical measures of market performance by grouping various equities, indexes, or other securities in standardized ways. Our team mastered not just the general principles, but the client’s specific IP around composite analysis.
While the product was primarily used internally as an alternative to spreadsheet-based calculations, it also served select external clients. Our team maintained the system’s reliability for both internal and external users while continuing to enhance its capabilities according to the roadmap.
The Results
The partnership delivered several key advantages over the traditional approach of hiring a replacement full-time engineer:
First, the client achieved higher development velocity thanks to access to our larger team rather than relying on a single engineer. This meant faster progress on their product roadmap and quicker response to maintenance needs.
Second, because our services were provided on a fractional basis, they achieved these improved results at a lower overall cost compared to a full-time hire. This demonstrated the value of our flexible resourcing model for specialized technical needs.
Most importantly, we ensured continuity for a business-critical system during a potentially disruptive transition. The client’s composite analysis capabilities remained stable and actually improved during what could have been a vulnerable period.
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