Activist investor Bill Ackman, the CEO of $11 billion Pershing Square Capital, has exited his massive, money-losing bet in Valeant Pharmaceuticals.

“At its current market value, the Valeant position represented 1.5% to 3% of the various Pershing Square funds; however, the investment required a disproportionately large amount of time and resources. As a result, we elected to sell our investment and realize a large tax loss which will enable us to dedicate more time to our other portfolio companies and new investment opportunities,” the fund said in a press release.

Pershing Square last held 27.2 million shares. The fund exited at a price of $11, according to CNBC’s David Faber. Shares of Valeant (VRX) fell more than 6% in the after-hours trading session.

Ackman will step down from the Canadian pharmaceutical company’s board. He’ll stay on with Steve Fraidin until the upcoming annual meeting. They will not stand for re-election. Ackman joined the board in March 2016.

In the press release, Pershing Square detailed steps that Ackman and Fraidin took during their time on the board.

• Replacing senior management with talented executives, including CEO Joe Papa, CFO Paul Herendeen and GC Christina Ackermann;

• Refreshing the board of directors with 10 new members;

• Returning the company to a current and timely filing schedule with the SEC;

• Receiving appropriate amendments and waivers under applicable credit agreements;

• Announcing a strategy to sell non‐core assets to improve the company’s balance sheet;

• Paying down ~$2.7 billion of net debt with the sale of non‐core assets and free cash flow generation; and

• Last week, priced a $3.25 billion bond refinancing and covenant waiver package which extends maturities and reduces the company’s exposure to floating interest rates.

Pershing Square had been invested in Valeant since February 2015. Pershing Square and Valeant teamed up together to pursue a takeover of Allergan. While their attempts were unsuccessful, Pershing Square profited handsomely after Allergan did a deal with Actavis.

Pershing Square got to know Valeant’s management after the activist hedge fund teamed up with the company to pursue a takeover of Allergan. While their attempts were unsuccessful, Pershing Square profited handsomely after Allergan did a deal with Actavis.

In a securities filing on March 17, 2015, Ackman disclosed that his fund owned 19.47 million shares, or a 5.7% stake. Based on that day’s closing share price, the position was worth close $3.9 billion.

Valeant’s share price first came under pressure after it had been criticized for its drug pricing. The stock then collapsed when in the fall of 2015 short-seller Andrew Left of Citron Research published a report asking whether Valeant was operating an Enron-like fraud.