– Newly announced Treasury Department rules aim to keep American corporations from dodging taxes by moving their headquarters to low-tax foreign countries while continuing to operate substantially in the United States.

But Medtronic, which helped spur the rules with its $49.9 billion purchase of Dublin-based Covidien, said Friday that the new rules will not materially affect the company’s finances.

In public notices, the Treasury Department said it changed the way it figures ownership of reincorporated foreign parents of former U.S. companies. The move was to close loopholes in corporate inversion deals that had allowed the new ­foreign companies to claim smaller percentages of shareholders from those former U.S. companies.

If old shareholders own more than 80 percent of new companies, the Internal Revenue Service treats them as U.S. businesses for tax ­purposes regardless of where they are based. Companies with 60-to-80 percent old shareholders also lose some ­advantages of reincorporating in low-tax havens.

Other rule changes seek to keep foreign parent companies from overstating the amount of business they do outside the United States. To get the tax breaks that companies like Medtronic seek in their reorganizations, they must do 25 percent of their business in the foreign country where they become headquartered.

The Treasury Department wants to curtail such accounting tricks as “stuffing” assets into foreign parents to make them appear bigger than they are. It also wants to expand U.S. taxes paid on “passive income” earned by new ­foreign parent companies.

In a news release, Medtronic said it saw no meaningful impact on its finances after a preliminary look at the rules. The company remains one of Minnesota’s major employers despite transferring its corporate headquarters from Fridley to Dublin in a deal sealed in January.

It said it would “continue to more fully assess [the new rules] and will provide appropriate disclosure concerning any potential material impact on the company as necessary.”