In 2010 the Irish brothers had an idea: They thought they could use clever coding to make it easier for internet startups to process payments online. They were right, transforming what was a monthslong, paperwork-heavy process into a point-and-click operation. Stripe, the company they founded, now sits behind a huge swath of the transactions taking place each day at Amazon.com, Instacart, Lyft, and more than 2 million other sites. The success has turned the Collisons into two of the youngest billionaires ever and raised the prospect in many observers’ minds that Stripe could pull off one of the largest initial public offerings in history.

A pair of autodidacts, the Collisons have used their wealth to explore areas far afield of payments. Stripe has focused on adding analytical muscle to carbon offset programs. It’s also invested in several promising carbon removal startups and built tools into its payments systems that let customers direct a portion of revenue to that end.