Bremer Financial Corp. CEO Jeanne Crain will step down from her position and exit the company in mid-May as the bank's sale to Indiana-based Old National Bancorp is finalized next month.

"As I reflect on this transition, I'm filled with deep gratitude for the relationships and shared purpose that have defined my time at Bremer," Crain, the chief executive and president of Minnesota's second-biggest bank, said in a post to her LinkedIn profile page Thursday.

"After four decades in the banking industry — and 13 years with Bremer, including the past eight as CEO, this chapter has truly been the most meaningful of my career."

A Bremer spokeswoman said Crain would not comment further, given the forthcoming sale and legal agreements in place after a civil settlement with the Otto Bremer Trust, the charity that largely owns the bank.

Bremer Bank is unique in its structure as the only bank in the country owned by a trust. The design allowed it to make a mark across the Twin Cities as a major giver as well as a prominent financial institution. However, it created some challenges for the bank in the modern financial services market, limiting its ability to make acquisitions or raise capital on the stock market as a publicly traded bank would.

A yearslong controversy and infighting prefaced the sale to Old National for $1.4 billion. In 2019, Bremer Financial began exploring a merger with Great Western Bancshares. Trustees disagreed with that move, believing a sale would be more profitable, and countered by putting the trust's stake in the corporation up for sale. The bank sued, touching off a five-year legal saga.

Minnesota Attorney General Keith Ellison conducted an investigation and intervened in the legal battle, alleging three trustees breached their duties. A Ramsey County District Court judge removed one trustee but ruled against nearly all of the allegations.

The case was settled in July. In November, Old National and Bremer announced a deal, creating what will be Minnesota's third-largest bank in terms of deposits. The $1.4 billion sale price, 78% in the form of Old National stock, undershot previous estimates that put Bremer's worth at $2 billion.

Publicly traded Old National, headquartered in Evansville, Ind., reported its progress toward the close in a securities filing earlier this month, putting the anticipated date at May 1. Shareholders approved the deal in March. Necessary regulatory approvals came last month from the Federal Reserve and the Office of the Comptroller of the Currency.

Old National's move to acquire Bremer came as the Indiana bank completed last year the purchase of the smaller CapStar Bank, with centers in Tennessee and North Carolina. That deal, which closed in April 2024, allowed Old National to add $3.1 billion in assets to its portfolio.

Old National spokesman Rick Vach said in a statement that Crain's status as a distinguished banking leader "set the bar exceptionally high for what it means to exceed client expectations and strengthen and support communities."

Crain's strong and steady leadership set up a partnership that will enable the company to build on Bremer's culture of community focus and outstanding service legacy, Vach said.

Crain joined Bremer in 2012. Her accomplishments include reinforcing Bremer's brand as a leader in agricultural banking, expanding Bremer's market share in eastern Wisconsin and navigating the financial and industry challenges of the COVID-19 pandemic.

Crain's résumé spans 40 years in the financial services industry, including as a chief executive of Marquette Capital Bank and a regional president at BMO Harris.

Crain said in her open letter Thursday that she treasured working alongside a team dedicated to customer and community service as well as the pursuit of ambitious goals. She said she has "full confidence in what lies ahead" as Old National buys Bremer.

Bremer oversees $16 billion in assets. It operates about 70 branches in Minnesota, North Dakota and Wisconsin.

In 2023, the Otto Bremer Trust gave away $105 million to more than 1,000 groups. Otto Bremer, a St. Paul businessman who died in 1951, established the trust in the 1940s.

Mike Hughlett of the Minnesota Star Tribune contributed to this story.