UPDATE 1-Ackman's hedge fund cooperating with U.S. on drug pricing probe -letter

(Adds details from letter, background on Valeant)
BOSTON, March 24 (Reuters) - Billionaire investor William
Ackman, whose hedge fund is one the of the biggest investors in
drug company Valeant, has been asked to supply information to
U.S. legislators probing price hikes in the pharmaceutical
industry.
Ackman told investors in his Pershing Square (NYSE:SQ) Capital
Management on Thursday that the firm received a request on
Friday from the U.S. Senate Special Committee on Aging as part
of an investigation into pricing of off-patent drugs.
"As you would expect, we will fully cooperate with the
committee's requests," Ackman wrote in the letter seen by
Reuters.
The letter did not say the request is directly related to
Valeant, but the Canadian company has sparked outrage among U.S.
lawmakers and the public in the last months for having pushed
through dramatic price hikes on older drugs.
Valeant did not immediately respond to a request for comment
on the letter.
In February, Valeant's interim chief executive officer
testified before Congress, acknowledging that the company's
decision to raise the price for two heart medications, Isuprel
and Nitropress, was too aggressive.
Ackman formally joined Valeant's board on Monday and
appeared to be taking full control of overhauling the company by
promising to file a delayed annual report by the end of next
month and finding a new chief executive.
Ackman's Pershing Square owns a 9 percent stake in Valeant
and has lost billions, on paper, as the company's stock price
tumbled some 85 percent in the last year amid questions about
its pricing strategy plus its business and accounting practices.
This week Valeant said Michael Pearson (LON:PSON), its long-time chief
executive officer and the architect of the firm's aggressive
mergers and acquisitions strategy, will be leaving the firm as
soon as the board finds a replacement.
Ackman told investors that he dispatched two of his staffers
to Valeant's Bridgewater, New Jersey headquarters immediately
after a disastrous earnings call on March 15 where the company
cut its forecasts and said it could be close to default.
The letter was attached to the firm's annual report which
said there are no plans to abandon the firm's strategy of making
concentrated bets on a small number of companies even after last
year's poor performance.
So far this year, Ackman's Pershing Square Holdings fund has
lost 25 percent, largely because of the drop in Valeant which is
down nearly 70 percent this year.