Medtronic Inc. captured global attention this month with its proposed $42.9 billion deal to acquire Irish medical firm Covidien Inc., while also cutting its federal taxes by making Ireland its financial headquarters. But the Fridley-based medical device maker is not the first Minnesota corporation to make the leap overseas.

Ten months ago, Eden Prairie-based 3-D printing firm Stratasys merged with Israel-based Objet Ltd. and changed its official headquarters to Israel, which has a lower tax rate. The move saved Stratasys $3 million a year.

And in 2012, the water technology company Pentair merged with Tyco Flow Control and “re-domiciled’’ its corporation from Golden Valley to Switzerland. That merger — accomplished through a tax-free “Reverse Morris Trust” — lowered Pentair’s corporate tax rate from 29 to 24.6 percent.

Determined to save even more, Pentair relocated again on June 3 from its Swiss headquarters to Ireland, which has a tax rate of roughly 12.5 percent.

Until Medtronic’s blockbuster Covidien deal was announced on June 15, these type of corporate relocations did not attract significant attention, in part because the operational headquarters and most employees typically remained where they had been. That’s all changed, as lawmakers and the Obama administration focus on the billions of dollars Medtronic’s move will cost the U.S. Treasury.

“The issue is now under the microscope,” said Mark Henneman, vice president of the St. Paul investment firm Mairs and Power, which owns stock in Medtronic, as well as Pentair and Stratasys. In changing domiciles, Medtronic, Stratasys and Pentair have joined a growing list of U.S. firms looking to reduce their tax debt to Uncle Sam.

Bloomberg News estimates that 44 companies have pursued similar corporate “inversions” or “reverse trust” strategies. Meanwhile, employees, investors and lawmakers are scrambling to grasp the practical effects of complicated tax strategies on jobs, capital gains and U.S. tax policies.

“Wall Street absolutely loves this deal” because of the possible corporate tax cuts and profit boost, said Henneman about the Medtronic-Covidien merger. But shareholders face their own tax issues.

Depending on which legal tools are used to structure an international merger, some mutual fund and individual stockholders could face taxes, Henneman said.

That’s the case with Medtronic, which plans to use something called a “corporate inversion” to legally relocate its headquarters to Ireland. “I have a few clients who are very upset about it. With this being a taxable event, we have a number of shareholders who are now looking at a significant capital gains tax.”

In contrast, Pentair’s deal resulted in tax-free transactions for shareholders, Henneman said.

“Frankly, the Pentair/Tyco deal was a lot easier to understand. It was merging businesses that were certainly quite related to each other,” Henneman said. “With Medtronic and Covidien, the clarity is not quite there.”

Pentair spokeswoman Marybeth Thorsgaard said that a review was conducted in 2013 “to determine the most appropriate and bene­ficial jurisdiction and tax residency for Pentair going forward.”

That jurisdiction proved to be Ireland, she said. The country has corporate tax rates as low as 12.5 percent. The U.S. hit on corporations’ overseas earnings coming back into the states brings the total tax bill to a stinging 35 percent.

In Washington, these tax-motivated deals have lawmakers demanding answers.

“My worry is that more companies will do this” and take jobs out of the United States, Sen. Amy Klobuchar, D-Minn., said in an interview with the Star Tribune last week. “That is why I have been arguing that we need to do something this year, or early next year, to ­create positive [tax] incentives for [overseas] money.”

Lots of ideas in Congress

Proposals being bandied out in Congress range from revamping and simplifying the entire U.S. tax code to partial solutions such as one-time allowances that would let corporations bring back, or repatriate, overseas earnings at a much lower tax rate, as was done back in 2004. Other ideas include a permanent rate cut and pooling all repatriation taxes into one fund for fixing U.S. roads, bridges and highways.

Until there is a comprehensive tax fix, however, lawmakers worry that more corporations will turn to tax strategies that shift headquarters overseas, sometimes taking jobs with them, Klobuchar said.

“Some of these proposals have cost jobs in the United States. And our members [of Congress] are very concerned about that.”

She noted drug giant Pfi­zer’s recent proposal to merge with British pharmaceutical firm AstraZeneca. That deal would have moved the headquarters to Great Britain and slashed jobs in New York and other states. The idea infuriated Congress, which is why 14 senators promptly proposed the Stop Corporate Inversion Act of 2014 last month.

“Pfizer was the impetus for that,” Klobuchar said. The proposed legislation, which would have put restrictions around the merger, contributed to the blowback that caused Pfizer to pull the plug on the merger.

The Stop Corporate Inversions bill, however, is still making its way through Congress and could affect the Medtronic-Covidien deal. Medtronic would have the opportunity to walk away from the deal if U.S. tax law changes, the company said last week in a filing with the Securities and Exchange Commission. The tax-change clause also would come into play if both houses of Congress pass legislation that would treat the combined company as an American corporation for federal tax purposes, even if a law isn’t immediately signed by the president, Medtronic said.

“We have been very lucky" in Minnesota, Klobuchar said. "Pentair and Medtronic actually want to keep and increase jobs in Minnesota and the U.S. But that was not the proposal from Pfizer. That is why we support broad tax [reforms].”

Medtronic has said it plans to add jobs in Minnesota if its merger with Covidien is approved by stockholders and goes into effect.

Separately, Pentair’s U.S. employment jumped from 6,900 to 9,800 after the Tyco deal closed. Its Minnesota staff grew “slightly” to 1,800, with most staff additions occurring in Golden Valley, Thorsgaard said.