Generic drugmaker Mylan has made an offer of $ $28.86 billion in stock and cash to acquire rival Perrigo. A merger of the two major players would create a leader in specialty drugs and nutritional products with $15.3 billion in annual revenue, based on 2014 figures, Mylan's offer represents a 25% premium over Perrigo's April 3 closing price, the last trading day before the bid became public.

Robert Coury, Mylan's executive chairman, told news agencies the two companies had held several discussions about a proposed merger. Perrigo, long identified as a takeover candidate, confirmed that it had received an unsolicited offer from Mylan and said its board would meet to discuss the proposal.

Both former US drugmakers are now operating from overseas. Mylan relocated from the state of Pennsylvania to the Netherlands in March of this year after paying $5.3 billion for a unit of Abbott Laboratories. Perrigo moved from Michigan to Ireland in December 2013 after buying Elan for $8.6 billion.

The announcement of the latest proposed healthcare deal, according to Thomson Reuters data the largest this year ahead of AbbVie's nearly $21 billion grab for Pharmacyclics and Pfizer's planned $16.7 billion purchase of Hospira, has touched off speculation about additional transactions.

Some industry observers believe that Mylan is pursuing Perrigo in an attempt to to fend off an unwanted takeover bid by Israel's Teva. There is also speculation that Valeant and Sandoz' generics arms could be hounding the now Dutch-based drugmaker.

In a deal concluded last month, Perrigo bought Omega Pharma of Belgium for $4.48 billion, including debt. With the takeover of one of Europe's largest manufacturers of OTC drugs, the company said it rose into the ranks of the world's top five.