Pershing Square’s Bill Ackman has increased his stake in Valeant Pharmaceuticals’ vrx common stock by 30%.

According to a Feb. 5 filing with the Securities and Exchange Commission, Pershing added nearly one million shares of Valeant to its portfolio since the fourth quarter of 2015, increasing its stake from 8.5% of the company to 9%. That includes call options.

The bump comes after Ackman’s apology to investors in a January letter, where he wrote that it was a mistake not to sell Valeant in the summer, when the stock rose above $200. That was after Pershing recorded its worst year of returns in its history—losing 20.5% of net fees.

Despite the public and political scrutiny that Valeant faced last year, Ackman stood strong behind the pharma giant, buying additional shares. Ackman later trimmed his stake down from 9.9% to 8.5% in the third quarter, saying it was to create a year-end tax loss for investors.

Ackman reported 21,591,122 shares of common stock on Feb. 5. and 9,120,000 shares of unexercised options to buy more stock at a later point in time, adding up to a 9% stake in Valeant.

That’s a 30% increase in common stock since the end of the fourth quarter, though a 27% decrease in options.

Fellow hedge fund investor Leon Cooperman sold off his stake in Valeant completely, according to his 13F filing for Omega Advisors.

Brahman Capital on the other hand doubled down, adding another 3.7 million shares of Valeant to its portfolio, now totaling about 8.1 million shares.

Paulson and Company, founded by John Paulson, also increased shares in Valeant by 4.4 million, to 13.3 million.