C3 Rebalancer

The Problem

Portfolio rebalancing workflows at wealth management firms are often manual: spreadsheets, inconsistent logic, error-prone steps, and time-consuming output review. Advisors spend hours each month on what should be a systematic process.

The Solution

Built a Python-based rebalancing engine that ingests portfolio/account data, applies allocation logic and constraints, and produces recommended actions in a consistent, auditable format. The tool transforms a multi-hour manual process into a few minutes of automated analysis.

Product Decisions

• Prioritized auditability over speed—every output can be traced back to inputs
• Built for batch processing to handle multiple accounts efficiently
• Used Excel as the output format for advisor familiarity and compliance needs
• Separated business rules from data ingestion for maintainability

Architecture

Technical Highlights

• Deterministic logic engine producing auditable, reproducible outputs
• Robust input validation with edge-case handling for malformed data
• Batch processing capable of handling 100+ accounts in a single run
• Clear separation of concerns: rules vs data ingestion vs outputs
• Exportable outputs in advisor-friendly formats (CSV/Excel)
• Configurable allocation constraints and thresholds

Results & Outcomes

• Paid $5,000 by employer for delivering the production-ready tool
• Reduced monthly rebalancing time from hours to minutes
• Eliminated manual calculation errors and improved compliance confidence
• Being positioned for marketing to other Northwestern Mutual partner firms

What I'd Do Next

• Add web-based dashboard for real-time portfolio monitoring
• Implement tax-loss harvesting suggestions
• Build API layer for integration with custodian platforms
• Create advisor-facing UI for non-technical users