In a blog, Reich says that he is leaving Simple in a "wonderful spot as a business". He will stay on as a board member and strategic advisor, with chairman Dickson Chu becoming interim CEO.

Reich first pitched the idea of Simple to co-founder Shamir Karkal a decade ago, spotting an opportunity in the widespread public disillusionment with traditional banks in the wake of the 2008 economic crisis.

With a strong background in technology, the founders believed that they could do better, and in the words of one-time CTO Alex Payne, build "a bank that doesn't suck".

After several years during which the idealistic team discovered the complexities of the banking market, Simple opened its virtual doors to much fanfare in 2012.

But, having pitched itself as an outsider, the startup quickly became subsumed into the big banking world, acquired by BBVA in 2014 for $117 million, albeit continuing to operate as a standalone business.

Last year, Reich admitted that, since then, Simple had become bogged down in rebuilding its core infrastructure and transferring accounts to new US banking partner BBVA Compass. He promised a return to the firm's tech roots, a move which involved laying off 10% of staff.

In his goodbye blog, the co-founder insists that Simple has overcome its recent challenges and returned to focusing on new features that benefit customers, adding that "financially, we've never been stronger".

He continues: "Simple is in a wonderful spot as a business and is on the right track as a product. If there is any time to leave, leaving on a high note feels right. It’s not that there are no more interesting problems for Simple to solve, but that I’d rather focus on my life and my family.

"Over the past decade, Simple has been my surrogate family. And more frequently than I’d like to admit, work has come ahead of my personal life. We’re only in this world for a short period of time and I’m in a position where I’d like to spend some time doing the things I’ve delayed.

"I’d like to start a family and be present as a father. Last year, my wife and I bought a small rural property and I’ve been spending any spare time working on projects. Working with my hands has been cathartic and I’d like to see more proudly-earned calluses in my future."