"Optus Bank hasn't grown the way CEO Dominik Mjartan expected it to when he joined the company seven years ago. It's grown differently, and more rapidly, than anyone might have imagined.

The South Carolina-based bank, one of about 20 Black-owned banks in the country, was on "life support" in 2017, Mjartan said. Now, Optus has increased its assets by more than 1,000%, raised over $100 million of equity and chipped its way to a profitable business plan.

So Mjartan is stepping down.

'There have been so many moments... over the last year where I thought, "This is the time," Mjartan said.'"