(Adds investor details, Allergan comment)
By Svea Herbst-Bayliss and Caroline Humer
BOSTON/NEW YORK, Aug 22 (Reuters) - Investors owning 31 percent of shares of Allergan Inc have asked the company to call a special shareholder meeting, activist shareholder William Ackman said on Friday, giving the hedge fund manager a victory in his fight to acquire the Botox maker.
Ackman, whose Pershing Square Capital Management is Allergan's largest shareholder, said 35 shareholders including some of Allergan's "longest-standing" and "largest" investors handed in paperwork on Friday to compel Allergan to call the meeting.
Pershing Square and Valeant Pharmaceutical International Inc made a $52 billion hostile offer for Allergan in April. Since then Allergan has been fighting for investor support for its own stand-alone plan that includes cost cuts and making an acquisition of its own.
Meanwhile, Ackman has been working to sign up enough shareholders and said that Allergan, under its bylaws, is required now to call the meeting no later than Dec. 20.
Pershing Square also said on Friday that it filed a lawsuit in Delaware to require Allergan to schedule the meeting, anticipating that the company would likely fight doing so. Ackman and Valeant's cash and stock offer is now worth $49 billion.
Allergan said in a press release that it would review the requests from shareholders in connection with Pershing Square's meeting request and expects to report the results promptly after its review.
Allergan also said that Ackman and Valeant's offer undervalues the company
At the meeting, Ackman hopes to replace the bulk of Allergan board members with his own slate of directors who might agree to the takeover deal and to force Allergan to open discussions.
Ackman's lawsuit is the latest legal tussle for the companies and follows Allergan's insider trading suit against Valeant and Ackman filed in federal court in California on Aug. 1.
DELIVERING THE PAPERWORK
Friday's move, in which Valeant and Ackman delivered the shareholder paperwork to Allergan's headquarters in Irvine, California, satisfies Allergan's bylaws that at least one quarter of its shareholders request the meeting, Ackman said.
The hedge fund manager, who called the task of filling out the paperwork "burdensome," said one shareholder, whose paperwork totals 174 pages, had to deliver 85 signatures.
T. Rowe Price Associates, The Vanguard Group, State Street Global Advisors and BlackRock Institutional Trust Company are the next largest shareholders after Pershing Square.
While some Allergan shareholders have sold holdings since the deal was announced, Ackman said many of the shareholders who back the meeting have owned Allergan stock since before he and Valeant Pharmaceuticals unveiled their takeover deal on April 22. More investors may still fill out the paperwork, he said.
Analysts had expected Ackman to gather more than 25 percent of the votes after two large proxy advisory firms urged investors to join Ackman in calling for the meeting.
(Reporting by Svea Herbst-Bayliss and Caroline Humer; Editing by Chris Reese and Leslie Adler)