Reflecting across 25 years of Minnesota’s business landscape, it’s easy to focus on what was lost. Honeywell. The St. Paul Companies. Northwest Airlines. Maybe Valspar.

Indeed, in 1992, when the Star Tribune published its first detailed ranking of Minnesota’s largest publicly held companies, 178 firms were traded on major exchanges. This year’s Star Tribune 100 lists just 84, about half as many.

But civic leaders and top economists say that they see no cause for alarm, and that big blows often have been replaced by bigger gains.

“We’ve had a resilient, dynamic economy,” said economist Myles Shaver, a professor of business strategy at the University of Minnesota. “It’s one of the things that sets our economy apart. We’ve been home to these big companies that have reinvented themselves and we’ve replaced them.”

The quarter-century history of the ST100 reveals how the breadth of companies helped the state boom during the Go-Go ’90s, weather the dot.com bust and show more buoyancy through the foreclosure crisis and Great Recession.

While the list has shrunk, the defining attributes of the state’s top companies remain essentially the same: a high concentration of public and private Fortune 500 companies, an array of varied industries and a highly educated workforce.

Through the years, Maplewood-based 3M has been a constant, never dropping below sixth in the revenue ranking. Though long known informally as 3M, the company officially changed its name from Minnesota Mining and Manufacturing in 2003.

Twenty-five years ago, the med-tech boom had yet to arrive. Dayton Hudson led the pack in revenue, at $16.1 billion, a perch its successor Target Corp. maintained until it was unseated by UnitedHealth Group in 2007.

As for UnitedHealth, few would have predicted its exponential growth. The Minnetonka-based health insurance company first cracked the top 10 in 1994 and crossed the $100 billion threshold eight years later.

As one measure of its heft, last year’s revenue of $157.1 billion is more than the combined sales of all 100 businesses listed in the newspaper’s inaugural ranking, by a cool $54.7 billion.

This year, UnitedHealth accounts for 31 percent of the revenue generated by all of the companies.

“I look at the relative size and scale of what’s being added to our Minnesota-based companies in terms of net revenue and net profits through organic growth, through acquisitions, through joint ventures and alliances we’re seeing more of,” said Jeff Cotton, Minneapolis managing partner of Deloitte, the accounting and consulting firm.

“Compared to what it was like 25 years ago, we’ve seen some incredible companies grow over that time frame. Our economy is strong, performing at a high level, high workforce participation, and low unemployment vis a vis other parts of the country,” he said. “The number of industries and sectors that are based here positions us well for the future, but has also served us well to this point.”

Shaver has spent several years analyzing Minnesota’s “headquarters economy,” a distinction that has been at least a century in the making. It consistently ranks both as having among the highest concentrations of Fortune 500s per capita and in relation to the state’s economy.

In 1955, the starting point for Shaver’s research, the state had 11 Fortune 500 companies. Last year, there were 17. More telling, Shaver noted, is that at least 50 Minnesota companies have come and gone from that list during that time. The turnover, he said, has had a positive impact overall.

“Yes, we’ve lost Fortune 500 firms, but we’ve been very active in replenishing them,” Shaver said. “That experience is very different from most other northern industrial states that look like us.”

Yet the churn has meant a decline in the number of women in key leadership positions, said Joann Bangs, an economist and dean of the business school at St. Catherine University. Bangs is in her ninth year of compiling a census of businesswomen in leadership positions.

As more large firms have merged or moved headquarters out of the state, the number of companies with no women on either corporate boards or executive spots has increased. In 2008, when the survey began, there were 16 companies in the “double-zero” category. Last year, there were 20.

“Those companies on the bottom of the list have become so small and they tend not to have much diversity in leadership,” she said. “A lot of that is because they don’t have boards or they just have a few people on them or they only have one or two executive officers.”

Still, there has been incremental improvement. The number of female CEOs has jumped from four in the survey’s first year to six in 2015. As far as board seats, 14.2 percent were held by women in 2008. Last year, it was 15.5 percent.

“You have no idea how that little change excites us,” Bangs said. “We have had some progress, but it always feels like we’re dragging against those [smaller] companies.”

Not every headquarters that moves out of state results in huge employment losses. Many companies leave an experienced workforce and significant operations behind.

When Norwest Corp. and Wells Fargo merged in 1998, the combined company chose the Wells Fargo headquarters in San Francisco. However, the company still has about 20,000 employees in Minnesota.

Honeywell’s Golden Valley facility is the global headquarters for thermostats and other control systems. Medtronic is expected to remain a top Minnesota employer, maintaining much of its corporate power base in Fridley despite moving its headquarters to Dublin, Ireland.

On the flip side, many of the Star Tribune 100’s largest publicly held companies have expanded their footprints by going on their own buying binges.

UnitedHealth Group, which has been growing by acquisition for a decade, made its largest deal in history in 2015 with the $14.3 billion purchase of the pharmacy benefits management company Catamaran Corp.

Likewise, Ecolab’s acquisition of Nalco Holding Co. in 2011 was its largest, and Toro’s 2014 purchase of Boss snowplows was a historic move. MTS Systems earlier this year announced its biggest deal ever when it made a play for PCB Group Inc.

Looking ahead to the half-century mark, it’s anybody’s guess what companies might fade away and what upstarts might be ready to rise on Star Tribune 100. Technology, innovation, flexibility and growth will dictate success.

The future of mining and jobs in northern Minnesota remains a pressing concern. Manufacturing, agriculture and other export-based businesses have hit a rough patch in recent years with low commodities prices, a slack in global demand and a strong dollar.

The merger and acquisition frenzy that recently caught Valspar in a deal to become part of Cleveland’s Sherwin-Williams hasn’t shown signs of slowing. And sizable spinoffs among the state’s largest companies likely will continue to alter the number of firms calling Minnesota home.

“This is the dynamic of companies,” Shaver said. “They grow, they shrink, they merge. It’s a normal part of our economy. In some ways, if that wasn’t happening, that would be a problem.”

Cotton said 45 percent of Deloitte’s business comes from companies that operate in the consumer or industrial product space, which he believes will remain an important area for the state moving forward.

“Over the last two or three years, management and boards have been back focused on strategy: how to grow through acquisition, how to innovate both internally and externally, how to be a place that is attractive to not only customers, but to their people and to the capital markets,” he said.

“The focus is back where it used to be when I started my career so long ago,” he said. “I’m pleased and cautiously optimistic about the future here.”