The action starts at 4 a.m. Twin Cities time on Tuesday, and will end several weeks later with the birth of one of the world's largest health care companies.

That's assuming all goes according to plan. On Tuesday morning, executives with Minnesota med-tech giant Medtronic and Dublin-based health care supplier Covidien will urge their shareholders to approve a deal to unite the companies under a new corporate parent based in Ireland. The deal also needs approval from an Irish court, which could take several weeks.

Following those steps, all shares in Medtronic Inc., a company born in an old boxcar garage in northeast Minneapolis 65 years ago, will be canceled.

In their place, Medtronic shareholders will receive stock in a new Irish-domiciled, multinational conglomerate called Medtronic PLC, with top executives continuing to work at offices in Fridley. The stock will trade under the same New York Stock Exchange ticker, MDT, and the new shares are expected to open at the same price as the old Medtronic Inc. shares closed on.

Medtronic will be paying the equivalent of about $48 billion for Covidien's large catalog of general hospital and surgical supplies sold around the world. For shareholders supporting the deal, the hope is that the new company will be more valuable than either one standing alone, and that financial advantages inherent in setting up global operations in a low-tax country like Ireland will free up capital for investments in new jobs and plants in Minnesota and across the U.S.

Medtronic PLC will employ 87,000 people with operations in more than 150 countries.

With combined revenue of roughly $27 billion, the new company will have a market capitalization just north of $100 billion. That would make Medtronic more valuable than iconic American brands like McDonald's and Honeywell International on a market-cap basis.

But the new company will remain in the corporate shadow of health care behemoth Johnson & Johnson, which boasts a market capitalization approaching $300 billion, making it one of the 10 biggest companies in the world, according to global corporate rankings complied by Financial Times.

Voting starts in Dublin

On Tuesday, Covidien's shareholders will gather at the posh Conrad Dublin hotel to vote on whether to accept Medtronic's offer of $35.19 in cash and 0.956 shares in the new Medtronic stock in exchange for each share of their old Covidien holdings.

Covidien needs approval from the owners of 75 percent of its 453 million shares to move forward.

The purchase price, negotiated by Covidien CEO Jose Almeida and Medtronic CEO Omar Ishrak between April and June 2014, was a premium of 29 percent over Covidien's stock price at the time.

"Mr. Almeida told Mr. Ishrak that Covidien has significant value as a stand-alone company and that Medtronic would need to offer a compelling premium in order for the Covidien board to approve a transaction," investment advisory firm Glass Lewis & Co. wrote in a note to investors, summarizing company statements in securities filings.

On June 14, the Covidien board of directors approved the buyout. Almeida stands to earn $54 million as part of a golden parachute that Covidien shareholders will vote on separately in a nonbinding vote, the companies' proxy statements to shareholders say.

Four hours after the voting in Dublin, owners of Medtronic will gather at 8 a.m. in the Hyatt Regency on Nicollet Mall in Minneapolis to decide the future of their 984 million shares. Many have already voted in favor in advance, though the company can't reveal where the vote tallies stand. The company needs approval from 50 percent of shares to move forward with the deal.

Despite unrest among longtime shareholders who will be hit with a large capital gains tax, Medtronic investors are expected to easily approve the deal because the lion's share of the company is owned by institutional investors whose tax impact will be lower because they acquired the stock at higher prices.

Mark Henneman, a mutual fund manager with Mairs and Power in St. Paul, said the firm will vote in favor of the acquisition with the shares it owns. "Our analysis indicates that Medtronic is $8 [per share] more valuable combined with Covidien than it is by itself," Henneman said. "The value of the merger is greater than the tax impact" for most shareholders.

Medtronic's share price has grown 20 percent since the deal was announced in June, which likely comprises much of the increased value predicted by Mairs and Power. But Henneman acknowledged that the increase in price won't make up for taxes owed by shareholders and retirees who have held the stock for decades.

"The tax impact to them is probably greater than the benefit they will receive from the merger. And so a lot of them will probably vote against it," he said. "The initial reaction from people was kind of angry."

Medtronic shareholders will also cast nonbinding votes on compensation for two dozen Medtronic executives who will face a hefty federal excise tax on their stock options — roughly $73 million worth, including $27 million to Ishrak.

Both the total value of the deal and the executive payments have grown since initial reports because they're based in part on the value of the rising Medtronic stock.

'90 percent positive'

Some upset shareholders criticized the deal at Medtronic's annual meeting in August because it will expose them to capital gains taxes while shielding corporate executives from special excise taxes.

Among the critics was Minneapolis corporate consultant David Schall, who is acting as a proxy for his father, the longtime former Medtronic board member Richard Schall. David Schall said he plans to vote in favor of the deal, because the two companies will be more effective when joined, and the excise-tax costs are an "unintended consequence" of federal tax policy for inversions.

"I think the two companies together are more powerful than the two companies separate," he said. "It's going to pass. It was going to pass even with a whole bunch of itchy individual shareholders. I'm sure this will get 90 percent positive."

Joe Carlson • 612-673-4779

Twitter: @_JoeCarlson