How sending handwritten letters created a $1bn firm

This week we speak to Alexander Rinke, co-founder of German technology company Celonis. When Alexander Rinke wanted some of the world's biggest companies to employ his small start-up business he came up with a novel approach - he would send their bosses handwritten letters. "We knew if we sent an email it could just be deleted," he says. "And if we sent out typed letters then their secretaries would open them, and bin them as junk mail. "But with a handwritten note, it seems more personal, it could have been a letter from a family member, or a friend." Alexander launched Celonis when he was 22 with two friends, Martin Klenk and Bastian Nominacher, in 2011 after they had finished maths and computer science degrees at the Technical University of Munich. Expanding on a project they had worked on as part of their courses, Celonis is a hi-tech data mining company that uses software and artificial intelligence to monitor the performance of businesses, to help them become more efficient and work better. In very simple terms, Celonis's software will monitor a company's computer system, and find out things such as which employees are being unproductive, which suppliers are too slow, and which production processes could be streamlined. The three friends were confident about what they could offer businesses, but they just needed to get themselves noticed. They worked like a treat, leading to meetings with some of the largest companies in Europe. Today, eight years later, Celonis's customers include BMW, Exxon-Mobile, General Motors, L'Oreal, Siemens, Uber and Vodafone. And after securing an additional $50m (£39m) of investment last year, Celonis says it is now valued at more than $1bn (£780m). Born and raised in Berlin, Alexander says he started his first company when he was just 15, supplying tutors to high school students. "It was great to get my first idea of how a business ran," he says. "But ultimately I knew it wouldn't last forever." Fast-forward to 2011 in Munich, and Alexander came up with the idea for Celonis when, as part of their studies, he, Martin and Bastian were helping a real world business improve its customer service. The three students found that the firm was taking about five days to come up with fixes to problems, and they thought there must be a quicker way. "We interviewed people in the company to try and understand why it took so long," says Alexander, who is now 29. "But we quickly realised that no-one was going to take the blame.