Patelco's financial condition has improved significantly under Burn's regime. Prior to his joining Patelco in 2009, the credit union had reported a $58 million net loss in 2008 and had already lost $26 million in the first two quarters of 2009.

Burns righted the ship with a net profit of $24.6 million in 2010 and record profits of $55.5 million to end 2012.

Burns said the decision has nothing to do with Patelco's recent Distributed Denial of Service attacks. In fact, he said, he'll be joining four other credit union CEOs in Washington later this week at the Treasury Department to participate in an FBI briefing on the topic.

“We dealt with it extremely well, and I think we've positioned ourselves as one of those go-to credit unions who understand this thing is serious and it's not going away,” he said about the DDoS attacks.

Mid-July is when Burns said he expects to make the transition. He'll stay longer if the board is unable to recruit a suitable replacement for the 247,000-member credit union, but he said he also is free to leave early if he finds the right opportunity.

While he wants to remain a credit union CEO, Burns said he's not necessarily looking to move up another asset class.

“I have the option to move to an organization that really entices me that may not be $3 billion,” he said.

Burns took over at Patelco in May 2009. He had been CEO at the $1.3 billion Technology Credit Union in San Jose, Calif.