Kristi Mitchem, CEO of Wells Fargo Asset Management, is resigning, a spokesman confirmed in an email.
Ms. Mitchem will leave Thursday, after having joined as CEO in June 2016.
Ms. Mitchem will join BMO Global Asset Management as CEO, effective March 18, succeeding Richard Wilson, who will retire from the firm, BMO announced in a news release Wednesday. She will report to Joanna Rotenberg, group head, BMO Wealth Management.
WFAM will now be led by interim co-CEOs Kirk Hartman, chief investment officer of WFAM, and Nico Marais, president and head of multiasset solutions, the spokesman said.
Ms. Mitchem's departure comes about a year after WFAM restructured its distribution team ahead of the retirement of Amru Khan, its head of institutional sales. Mr. Khan retired in April.
As of Dec. 31, WFAM reported $466 billion in assets under management, down 8% from a year earlier, "primarily due to equity and fixed-income net outflows, the sale of Wells Fargo Asset Management's ownership stake in The Rock Creek Group LP and removal of the associated AUM, and lower market valuations, partially offset by higher money market fund net inflow," said a Jan. 15 earnings news release from parent Wells Fargo.
The company separately announced to employees in September that it plans to cut its workforce by about 5% to 10% within three years.
Ms. Mitchem's departure is not related to job-cutting measures, as "she left because she found another opportunity and we wish her well," the Wells Fargo spokesman said. He declined to comment further.
— Bloomberg contributed to this story.