A decision may be announced as soon as Monday, said the people, who asked not to be identified discussing a private matter. While Perrigo is currently the most likely buyer for Dublin-based Elan, no final decision has been made and competitors such as Allergan Inc. and Mylan Inc. could still secure a deal, the people said.

Buying Elan, whose current market capitalization is $7.64 billion, would allow a U.S. company such as Perrigo to take advantage of its Irish headquarters to re-domicile itself in Ireland, where the rate of corporate income tax is 12.5 percent. Elan’s main product is Tysabri, a drug for multiple sclerosis for which the company receives royalties from Biogen Idec Inc., the marketer of the drug.

Arthur Shannon and Bradley Joseph, investor-relations representatives for Allegan, Michigan-based Perrigo, couldn’t immediately be reached for comment. An Elan representative couldn’t immediately be reached for comment.

Elan earlier this year began an auction process to seek a buyer after Royalty Pharma, a firm that invests in the income streams from existing drugs, spent four months trying to acquire it. Royalty has been exploring ways to partner with an eventual acquirer of Elan, allowing it to take on royalty streams while the buyer uses the Irish company’s corporate shell, people familiar with the matter said in June.

Elan’s shares rose 42 percent this year to 11.14 euros in Dublin as of July 26. Perrigo’s shares advanced 29 percent to $134.23 in New York, giving it a market value of $12.6 billion.