As the new Wells Fargo towers in downtown Minneapolis were "topped off" Tuesday, the state's largest bank reinforced its investment in the Downtown East neighborhood by pledging "a significant amount of money" for the Commons park.

A construction crew from Minneapolis-based Ryan Cos. secured the top structural beam on the second of two 17-story buildings that will be offices for about 5,000 of the bank company's 20,000 employees in Minnesota. Then, they placed an evergreen tree on the beam, keeping with a construction tradition that's rooted in an ancient Scandinavian religious rite.

Dave Kvamme, chief executive of Wells Fargo's Minnesota unit, announced its financial commitment to the 4.2-acre Commons park that will be built just outside the front doors of the two towers.

"We are really excited about the fact that we are going to have the Commons out here soon," Kvamme said to hundreds of stakeholders and construction workers. "Now all we need is $22 million. … We are going to contribute to the Commons, and I know others are as well."

Kvamme declined to reveal a dollar amount until after he tells Minneapolis Mayor Betsy Hodges, who is currently traveling. But, he said, Wells Fargo has already determined its donation, and the sum is sizable.

"It'll be a great asset for our team members and for all the people in the downtown area," Kvamme said. "We don't have a lot of similar opportunities downtown."

The office buildings, with 1.2 million square feet of space, anchor the five-block Downtown East redevelopment of land previously owned by the Star Tribune and just next to the new Vikings stadium that's also under construction. The first of the buildings will be finished next January, with the second in March. The stadium is due for completion by the start of the 2016 season.

Park fundraising kicked into high gear last week after Hargreaves Associates, the San Francisco-based landscape architect hired by the city, revealed its design plans for the two-block park.

A key provision in the park-use agreement prohibits naming rights for any part of it, regardless of the involvement of donors. Lester Bagley, Vikings executive vice president of public affairs and stadium development, has said this was meant to prevent any conflict of interests between a park donor and a lucrative stadium sponsorship.

Even so, the towers offer a publicity opportunity to Wells Fargo during Vikings games. The bank's name will likely be visible from helicopters used by TV ­broadcasters.

"We believe it's an important opportunity for us to brand the buildings that we've invested $300 million into and are proud of," Kvamme said.

Ryan, the project's developer, is also building a parking ramp near the towers, apartments near the park and plans a Radisson Red hotel behind one of the Wells Fargo towers. The firm is removing asbestos from the old Star Tribune building so it can be demolished later this summer to make way for the park.

"There are cranes all over the city," said John Stiles, Mayor Hodges' chief of staff, who attended the ceremony. "These cranes are different because these cranes are transforming a part of downtown that had been nothing but surface parking lots and an empty promise for a long time."

Kristen Leigh Painter • 612-673-4767