Brian Dunn, CEO and director of Best Buy, announced his resignation today, according to Wall Street Journal reports. Dunn and Best Buy stated the resignation was a “mutual agreement” and wasn’t elicited by any disagreement or hostility. Director Mike G. Mikan will assume the role of interim CEO.

Heavy volumes of trading following the news, which broke around 9:35 am EST, lead to a 3.1 percent increase in Best Buy stock. Dunn’s resignation comes just a few weeks after the tech giant announced a change in its business model from “big box” store to smaller formats that focus particularly on mobile devices.

Internet tech companies with lower overhead have hurt Best Buy’s bottom line in recent years, making it nearly impossible for it to compete in the competitive tech market. Best Buy announced in March it plans to close 50 stores this year, and will test its revamped business model at stores in San Antonio and Minneapolis.

Dunn served as the Best Buy CEO for three years. He worked at Best Buy for a total of 28 years, starting as a store clerk and working his way up. “I have enjoyed every one of my 28 years with this company, and I leave it today in position for a strong future,” he stated in a press release. “I am proud of my fellow employees and I wish them the best.”

Mikan has served on the board of directors since 2008. He was formerly the CFO and Executive VP of UnitedHealth Group Inc. and CEO of Optum, a company affiliated with UnitedHealth. The company has formed a search committee responsible for finding a permanent CEO to replace Dunn. Mikan will assume the position of CEO until that time.

“The Best Buy team and I will be extremely focused on successfully managing this period of transition,” said Mikan, commenting on the future of Best Buy. “I want to assure our employees, customers and other key stakeholders that we will work together to achieve our company’s growth and profitability goals.”