Brothers Chaz and Arnie Englander started Model ML after building and selling two YC companies. What began as a tool to help them analyze deals has grown into a full AI-powered workspace aiming to replace the Microsoft Office Suite in financial services. And it's already being used by 10% of the world's top investment banks and private equity firms.In this conversation with YC Partner Gustaf Alstromer, they discuss going from internal tool to production platform, the power of perseverance, and their ambition to build a billion-dollar company with just ten people.