In its fifth and biggest year yet, Twin Cities Startup Week attracted one group like never before: the largest companies in town.

From the first Startup Week in 2014, Minnesota’s big companies have sent their technologists, developers and engineers to attend the various technical panels and networking events put together by startup firms and related organizations, including Beta.MN and the U’s Minnesota Cup. They also donated space and money to those efforts and, in turn, harvested ideas and occasionally talent.

But this past week, managers at firms like U.S. Bank, Securian Financial, Allina Health Systems and Best Buy played much bigger roles in Twin Cities Startup Week and three other innovation conferences that were cross-promoted and attended by thousands of people.

For instance, the chief executives of General Mills, Cargill and Ecolab headlined events at the Food Ag Ideas conference. Walmart and Mayo Clinic joined Medical Alley, the trade group of Minnesota medical device companies, in sponsoring the Manova health innovations conference. And nearly every major company turned up to present and recruit at the Blacks in Technology convention.

“Startups empower people to pursue their own ideas,” Paige Benson, a recent University of Minnesota graduate, said after a Startup Week panel of executives from large and small firms. “It’s encouraging to know that bigger companies are looking to the entrepreneurial scene to pursue more of those ideas.”

For organizers, the rising participation of the region’s most powerful businesses in Twin Cities Startup Week validates the work they have done organizing and promoting startup firms. More broadly, it reflects an evolution in the way big businesses approach technological challenges and opportunities.

For decades, executives at big firms believed they needed in-house systems along with ideas and tech people they controlled. But as the rise of internet and mobile gadgets created more opportunities to deliver their goods and services, these executives realized their tech teams couldn’t do everything.

Tech executives at big firms locally also realized they were frequently reaching out to small firms in other parts of the country for help and needed to do more of that at home.

“A lot of us at the big corporations in town are participating in accelerators and other partnerships out on the coasts and, over the past year, we’ve had conversations about how do we do more in the Twin Cities and grow the ecosystem in our own backyard,” said Elizabeth Carraro, director of digital strategy and partnerships at Securian Financial in St. Paul.

Carraro and executives from U.S. Bank, Thrivent and Allianz a few months ago started brainstorming about setting up a series of events for Startup Week tied to their work in financial technology, or fintech. The group pitched the idea to Beta.MN and to the leaders of several local fintech startups.

“We said, ‘If we do this, what would you like to get from it?’ so it wouldn’t just be about internal corporate marketing,” said David Ness, vice president of innovation at U.S. Bank. “They told us that one of the hardest things on their journey was early-stage funding.”

As a result, the financial executives expanded their planning. Initially, they thought about organizing five events, the minimum to qualify for a subject “track” that stands out on the agenda of more than 200 events in Startup Week. They wound up with 12 events — speeches, panels and parties — that stretched over four days. One highlight: a pitchfest hosted by Thrivent with a $75,000 prize for startups.

In one panel, Ness and two startup executives described the pros and cons of the partnering that happens between big and small firms. At another, a Wells Fargo executive described to startup firms how to get their foot in the door of a Fortune 500.

At yet another, three founders of local fintech companies Sezzle, ClickSwitch and Live.Give.Save described their search for customers, workers and capital.

A few months ago, a senior executive at Allina Health Systems approached Chris DuFresne, the technology manager who led an overhaul of the company’s website, to speak at Twin Cities Startup Week.

“I had heard of Twin Cities Startup Week but never participated,” said DuFresne, who worked at Target before joining Allina. “We have appreciated our work with small organizations and startups. They bring a lot of innovation into health care, especially from the consumer perspective.”

He agreed to create a 90-minute presentation of how Allina worked with small firms in the website transformation and asked executives from two Minneapolis-based firms, Matt Johnson of GoKart Labs and Ethan Otterlei of Zipnosis, to join.

They described four years of work that started first with Allina and GoKart and expanded to include Zipnosis, which provided an online diagnostic platform that was added to the site. The three imparted the ups and downs of their collaboration, including some painful decisions and bumps along the way.

“I distrust presentations where people don’t talk about the challenges that they faced. Everything doesn’t go swimmingly. Nothing does,” DuFresne said. “There’s always issues. There’s always opportunities. Just being upfront with those is how others learn.”

In health care companies, where work is complicated by privacy issues and regulations, revamping a website or incorporating an outside firm’s technology takes far longer than it might elsewhere. Melding Zipnosis’ diagnostic tool into the Allina site took a year, a period the executives described as a “sprint” by the industry’s time frame.

“The fact they did that sprint in a year is really impressive,” said Benson, the recent graduate, after the session wrapped. She interned at Blue Cross Blue Shield of Minnesota this summer and is about to join the company full-time. “Especially after working at Blue Cross, I can see how difficult it is to integrate innovation into a big company,” she added.

Mariana Quiroga, a former marketing executive at General Mills and 3M, attended the Allina session in part because she is thinking about starting her own firm that will focus on customer service in health care.

“The big companies have woken up and realized a lot of truly fresh ideas come from people at a startup who are unbiased, flexible and fast at doing things,” she said.