I was working on a program to calculate minimised Australian capital gains tax return for buying and selling shares. The core part is written as a set of custom PostgreSQL views and window functions. It is hosted by Django. I’ve built a minimal UI for it. Accountants and investors appreciate the tool, but I don’t have the time and money to take it further. I had estimated potential market in Australia from $100k to $1m revenue per year - not enough to start a startup. If interested in buying source code let me know. It supports stock splits and code changes