Allergan has done a U-turn on considering a massive bid for biotech firm Shire, the latest twist in a saga that has played havoc with pharmaceutical stocks this week.
Shire has already been approached by Japanese drugmaker Takeda, which said Thursday it had proposed paying about -42.4 billion ($60 billion) for the company.
Reuters then reported Thursday that Allergan, whose headquarters are in Dublin, was also considering a bid for Shire, citing unnamed sources. Allergan responded with a statement saying that it was "in the early stages of considering a possible offer for Shire."
The news sent Shire's shares skyrocketing as much as 12% in London trading. They closed up nearly 6%. Meanwhile, Allergan's stock in New York sank as much as 8.5%.
But Allergan later killed the speculation, saying in a statement that it "does not intend to make an offer for Shire." The company said it will continue "evaluating a full range of potential strategic actions that will create value for shareholders, such as divestitures, combinations and acquisitions."
Allergan shares trimmed their losses, closing down about 4%. Shire's stock sank more than 3% early on Friday.
Takeda's shares have also taken a beating from all the talk of a blockbuster offer. They closed down nearly 5% in Tokyo on Friday.
Shire said in a statement that it had received and rejected three different proposals from Takeda in the past month.
It said its board and management were "focused on fully evaluating internal and external opportunities to maximize value for shareholders, including any further proposals from Takeda."
If Takeda formally makes a takeover bid of $60 billion or more, it would be the biggest so far this year, according to data from Dealogic.
And if a takeover of that scale goes through, it would be the third biggest acquisition of a UK-traded company in history.
-- Alanna Petroff contributed to this report.