J.P. Morgan Chase & Co. announced today that Jamie Dimon will become CEO of the U.S. bank at year end.

Dimon, 49, currently president and COO, will succeed chairman and CEO William Harrison Jr., 62, as CEO. Harrison will continue as chairman of the board. The bank says that the change will take place about six months earlier than planned given the good progress made on successfully integrating the J.P. Morgan Chase and Bank One merger.

“With many of our merger milestones completed and financial performance improving significantly, I recommended to the board that we accelerate the transition,” said Harrison, in a release. “I’m looking forward to doing whatever I can to support Jamie and the senior leadership team as we realize the potential of this outstanding company.”

“Bill Harrison has been a great partner through this transition, and I look forward to his support and counsel in the future. I am very excited about the opportunity to lead this great institution,” Dimon added.