In an industry that is notoriously behind the times, a fundamental change is underway. This change is in response to new business demands, including: (1) The desire to price increasingly complex deals with increasingly large datasets; (2) The desire to integrate with 3rd party data to augment pricing models; (3) The desire for faster models and robust codebases that adhere to software development best practices. Excel fails miserably at these tasks. — Ditching Excel for Python – Lessons Learned from a Legacy Industry