;" />

Streamlining Index Rebalancing Through Code Refactoring

Traditional methods of rebalancing indexes often rely on outdated and inefficient tools, leading to increased costs and potential errors. This process can be optimised by leveraging modern programming techniques to save resources and reduce costs.


Ella is an Associate with 5 years of programming experience and 2 years of expertise in Market Infrastructure.

Ella Harding
Senior Consultant

Challenges in Traditional Index Rebalancing

Rebalancing methods often rely on tools that are not fit for purpose, such as legacy code and VBA. This can present several challenges:

  • Legacy code: Old, outdated, and sometimes hardcoded systems can often be inefficient and lead to unwanted errors.  
  • Lack of Version Control: Without proper version control, tracking changes, maintaining code integrity, and collaborating with team members becomes increasingly difficult. This can result in errors, inconsistencies, and a lack of accountability.
  • VBA (Visual Basic for Applications): While useful for automation within Microsoft Office, VBA can be slow and difficult to debug, making it unsuitable for large-scale financial calculations.
  • MATLAB: Known for its robust computational capabilities, MATLAB's high licensing costs can be prohibitive, leading many companies to seek alternatives to these  high-cost systems.

Benefits of Code Refactoring

Code refactoring involves restructuring existing code to improve its efficiency and maintainability without altering its external behaviour. Here’s how refactoring can enhance the index rebalancing process:

  1. Efficiency Gains: Refactoring legacy code into modern languages like Python significantly increases processing speed, leveraging extensive libraries designed for financial computations.
  1. Cost Reduction: Transitioning from expensive licensed software to open-source solutions like Python can greatly reduce costs while maintaining computational power.
  1. Enhanced Accuracy: Automated, well-structured code minimises human error, ensuring consistency and reliability in rebalancing.
  1. Scalability: Modernised code can handle larger datasets and more complex calculations, essential for growing markets and increasing data availability.

Practical Example: Refactoring VBA to Python

Consider a rebalancing process currently implemented in VBA. By refactoring the code into Python, you can:

  • Increase Processing Speed: Python’s performance in handling large datasets far surpasses VBA, reducing the time required for rebalancing.
  • Improve Readability and Maintenance: Python’s syntax is more readable and maintainable compared to VBA, facilitating easier debugging and updates.
  • Enhance Functionality with Libraries: Utilise powerful libraries like Pandas for data manipulation and NumPy for numerical calculations, streamlining the rebalancing process.
  • Implement Version Control: Using Git for version control ensures that changes are tracked, and code integrity is maintained, facilitating better collaboration and reducing the risk of errors.  

How Delta Capita can help:

At Delta Capita, we have extensive experience in helping firms overcome the challenges associated with traditional index rebalancing methods. Here’s how we can assist:

  • Tailored Refactoring Solutions We analyse your existing rebalancing processes and provide customised refactoring solutions, transitioning your code to modern, efficient languages.
  • Cost-Effective Implementations By leveraging open-source software, we help reduce your operational costs without compromising on computational power or accuracy.
  • Automated and Accurate Processes Our solutions automate the rebalancing process, minimising human errors and ensuring consistent and reliable outcomes.
  • Scalable and Maintainable Code We ensure that your rebalancing code is scalable, maintainable, and capable of handling larger datasets and complex calculations as your needs grow.


Refactoring code for index rebalancing is a strategic move that can lead to significant resource savings and cost reductions. By transitioning from outdated methods to modern, automated solutions, financial firms can enhance accuracy, scalability, and overall efficiency. Embracing code refactoring not only benefits the bottom line but also positions firms to better respond to the dynamic nature of financial markets.