Bill Ackman made one final trade at the end of 2015

Valeant’s business model has been scrutinized by many in Wall Street. Until now, Ackman has been a strong defender of Valeant, and even boosted his stake with a massive increase to the allocation in late November.

Ackman was not available for comment, and a company spokesman declined to say anything beyond the filing.

Ackman’s decision to sell a good part of his Valeant shares caps off what has been a tumultuous year for the investor. The past year has been a tough year for hedge funds. Meanwhile, Mr. Ackman used his own stake in Allergan to try and pressure its board to the merger.

Allergan sold itself to Actavis instead and in March of 2015, Ackman said he had made a sizable bet in Valeant.

The company is facing a congressional investigation in the USA over its pricing practices and has been forced to revise its 2016 outlook after ending a drug distribution agreement with the controversial Philidor mail-order pharmacy. The shares, purchased at an average of $196, hit a high of $262.52 in August. December saw the drug-maker’s shares recoup over 26% in value, but the momentum gained was short-lived.

The sales began on December 24, one day before Valeant disclosed that Chief Executive Officer Michael Pearson was being treated for severe pneumonia, and they continued every day this week. The company has named a group of senior executives as Valeant’s interim leadership until Pearson is returned to health. Valeant shares last traded in Toronto on Thursday at $157.68 (Canadian).

Pershing Square Capital Management the hedge fund operated by William Ackman cut its shares in Canada-based Valeant Pharmaceuticals to just 8.5%. Pershing Square has sold the shares in order to generate a tax loss for investors in two of its funds, and this move would lower investors’ 2015 taxes. The fact that Mr. Ackman, one of the biggest investors and a vocal supporter of Valeant throughout its crash, has reduced stake in the company will not be taken well by the market. JPMorgan Chase & Co. dropped their price objective on shares of Valeant Pharmaceuticals Intl from $265.00 to $225.00 and set an “overweight” rating for the company in a research note on Wednesday, November 11th.

In a recent regulatory filing Pershing said that its stake in Valeant is now equivalent to 8.5% of the company’s shares (or 29.1 million shares) valued at about $2.96 billion. Mid-October, a short-selling firm called Citron published a report accusing Valeant of an Enron-like fraud.

Valeant came into limelight after it was found that the company has increased the prices of two cardiac-care drugs by 525% and 212%, after taking hold of the medicines in February. He spent four hours in October arguing that it was undervalued, to little avail.

Also of note, according to the filing, Pershing Square’s two off-shore portfolios with notable Valeant holdings did not sell any shares.