Raúl Fernández del Blanco
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Experiments

Investment Ledger

Personal Finance & Portfolio Analytics

A personal tool that brings CSV exports from several brokers into a single ledger to keep track of an investment portfolio. An ongoing experiment.

Role
Personal project
Year
2026
Status
In progress
Category
Experiments

Context

When investments are spread across several brokers, each one has its own export format and its own way of computing returns. This experiment looks for a single, consistent view of the whole portfolio.

Approach

  • Import. Each broker’s CSV exports are normalized with pandas and loaded into a single ledger in DuckDB.
  • Analysis. Allocation by asset and by currency, and time-weighted (TWR) and money-weighted (MWR) returns.
  • Tracking. A dividend calendar and rebalancing alerts when the portfolio drifts from its target allocation.
  • Interface. A Streamlit app with interactive Plotly charts.

Outcome

It is an ongoing experiment for personal use. It serves as a test bed for working with heterogeneous financial data and for understanding in depth how the different return measures are calculated.