By David Benoit and Joseph Walker 

Activist investor William Ackman and Valeant Pharmaceuticals International Inc. pivoted strategy yet again as they moved to ratchet up the pressure on Allergan Inc. on Monday to succumb to a $52.7 billion takeover.

Mr. Ackman on Monday dropped an unusual plan announced last month for a straw poll of Allergan shareholders and will instead seek a more definitive vote to throw out a majority of the Botox maker's board. Meanwhile, Valeant Chairman and Chief Executive J. Michael Pearson said he was readying a hostile tender offer that could take the bid directly to shareholders if the Allergan board doesn't bless it, although it's not clear how his company's alignment with Mr. Ackman would affect that effort.

In April, Valeant announced an unsolicited offer for Allergan with support of Mr. Ackman's firm, Pershing Square Capital Management LP, which before that announcement built a 9.7% stake in Allergan. The Irvine, Calif.-based Allergan has resisted the overtures, questioning whether the two companies' business models made a good match.

On Friday, Valeant boosted its bid for Allergan for the second time last week, raising the cash portion of the offer after Mr. Ackman agreed to take a price cut on his own stake.

Allergan has yet to respond to either sweetened offer, but three weeks ago it rejected the original bid without meeting with Valeant. Allergan reiterated Monday that it would consider the raised bids and urged shareholders not to take any action.

Pershing Square had previously announced an unusual referendum that would have delivered a nonbinding vote, outside of typical corporate voting rules, looking to urge the company to engage in negotiations. Allergan had pledged to all but ignore such a referendum, but cannot ignore the official process Mr. Ackman is launching now. A special meeting to remove directors could happen anytime between early August and late November, Mr. Ackman said Monday. Directors were re-elected just last month and without a special meeting wouldn't be up for re-election until the same time next year.

When he earlier revealed the referendum, Mr. Ackman said a special meeting could take too long.

Mr. Ackman said Monday that Pershing Square now decided to forego the referendum because of concerns from Allergan shareholders that such a vote could trigger Allergan's so-called poison pill and would delay a special meeting. Allergan's poison pill limits Pershing Square's stake to less than 10% and could restrict talks between investors. The referendum was seen as a way to sidestep the pill in terms of investor discussions, but Mr. Ackman said in the end he couldn't tell institutional investors he was sure the pill wouldn't be tripped.

"It's not entirely clear if the poison pill applies to the referendum or not," Mr. Ackman said during a conference call with analysts on Monday. "Shareholders also told us they didn't want the referendum [because] it will delay the special meeting."

The attempt to seek the referendum had met some criticism, including from California Congressman Rep. Edward Royce (R. Calif.) who raised concerns about the plan in a letter to the head of the Securities and Exchange Commission.

Mr. Ackman said he made his decision to take a price cut, helping Valeant to boost its offer, after meeting other top Allergan shareholders on Thursday. Mr. Ackman said they told him they wanted a bid of $180 a share. Friday's offer would deliver Allergan shareholders, outside of Pershing Square, $179.25 a share in cash and stock.

Pershing needs consent from at least 25% of the company's shares to hold the special meeting. Mr. Ackman said the Thursday meeting included investors holding about 29% of the shares.

Mr. Pearson had already raised the possibility of a hostile offer and a fight over Allergan's board; his partnership with Mr. Ackman has largely been viewed as a way to get help in a campaign. Pershing Square didn't reveal which six board members it would seek to remove or name six candidates to replace them with.

Write to David Benoit at david.benoit@wsj.com and Joseph Walker at joseph.walker@wsj.com

Subscribe to WSJ: http://online.wsj.com?mod=djnwires

Valeant Pharma (NYSE:VRX)
Historical Stock Chart
From Mar 2024 to Apr 2024 Click Here for more Valeant Pharma Charts.
Valeant Pharma (NYSE:VRX)
Historical Stock Chart
From Apr 2023 to Apr 2024 Click Here for more Valeant Pharma Charts.