Ackman urges Allergan board to 'wake up' on Valeant talks

After months of staying largely silent on a deal he is trying to broker, billionaire William Ackman on Tuesday criticized Allergan's board of directors, urging them to "wake up" and at least listen to what potential purchaser Valeant Pharmaceuticals has to offer the Botox maker.

In a letter sent to Allergan's nine directors, Ackman said, "Your actions have wasted corporate resources, delayed enormous potential value creation for shareholders, and are professionally and personally embarrassing for you."

Read MoreIs Bill Ackman doubling down on Herbalife?

"The smell of strong brew is in the air, now is the time to wake up," he wrote in the letter which was released in a regulatory filing.

Allergan responded on Tuesday by reiterating its criticism of Valeant's offer and confidence in its course.

William 'Bill' Ackman, founder and chief executive officer of Pershing Square Capital Management LP, speaks during an event in New York, U.S.
Jin Lee | Bloomberg | Getty Images
William 'Bill' Ackman, founder and chief executive officer of Pershing Square Capital Management LP, speaks during an event in New York, U.S.

"Mr. Ackman's hyperbole, bluster and personal attacks do not change the fact that Valeant's offer is grossly inadequate and substantially undervalues Allergan. We recognize that what matters is value, and the Allergan board remains confident in the company's ability to deliver significantly more value than Valeant's offer," an Allergan representative said in a statement.

It has been five months since Ackman, whose $15 billion Pershing Square Capital Management hedge fund is Allergan's largest investor, announced he is working with rival drug maker Valeant.

Despite sweetened terms from Valeant, Allergan has steadfastly refused to sell itself to its rival, sued the company and Ackman and has tried to line up another potential partner.

Read MoreHostile Allergan bid:Cramer hopes Ackman whiffs

Now with his three-page letter dated Sept. 9, the New York-based hedge fund manager seemed to want to give this board one more chance to take action before a special meeting at the end of the year where he hopes to replace most of them with his own slate of directors.

Allergan, Apple top picks for hedge funds: Pro
Allergan, Apple top picks for hedge funds: Pro   

He told them they can still "rescue" their reputation by taking over the leadership from Chief Executive Officer David Pyott, who is in Ackman's words trying to "stymie" a transaction.

Allergan, Ackman said, has "distinguished itself in running the most shareholder-unfriendly, hostile defense process perhaps in the history of corporate America."

He listed what he considers Allergan's missteps, underscoring that the recent departure of the chief financial officer, Jeff Edwards, at age 53 was particularly worrying.

Read MoreI did not front-run Allergan stock, Ackman says

"The notion that Allergan should execute the largest acquisition in its history led by an investor relations executive is a frightening proposition," he wrote.

Ackman is the latest in a string of activist hedge fund managers who are resorting to penning strongly worded letters to board members as they push for change. Daniel Loeb, who runs Third Point, made these types of letters famous with missives about Yahoo before he won board seats and played a critical role in picking a new CEO.

By Reuters