Seth Klarman’s Baupost Group increased its stake in Atara Biotherapeutics based on its latest 13G filing with the Securities and Exchange Commission (SEC).

Based on the filing, Baupost Group currently owns 4,763,265 shares or 19.5% stake in Atara Biotherapeutics, a clinical stage biopharmaceutical company focused on developing treatments for serious diseases. The company’s initial focus is on muscle wasting conditions and oncology.

The hedge fund first acquired 2,495,913 shares of Atara Biotherapeutics based on its 13F filing in the fourth quarter of 2014. The biopharmaceutical company priced its underwritten public offering of approximately 3.63 million shares for $18 per share on February 12. Its underwriters were also given a 30-day option to acquire additional 549, 749 shares at the public offering price. Atara Biotherapeutics completed its underwritten offering on February 18.

Atara Biotherapeutics financial performance

Atara Biotherapeutics posted a net loss of $10.5 million or $0.67 per share during the fourth quarter of 2014. During the same period a year earlier, the company recorded a net loss of $3.6 million or $3.15 per share.

The company incurred $5 million expenses in research and development during the period, an increase from $2.3 million in the same period in 2013. Its general and administrative expenses also rose from $1.2 million to $4.5 million.

Last month, Atara Biotherapeutics obtained a breakthrough therapy designation for its optioned cytotoxic T lymphocytes activated against Epstein-Barr Virus (EBV-CTL) for the treatment of EBV-associated lymphoproliferative disease (EBV-LPD), a serious and life-threatening condition.

Atara Biotherapeutics recently appointed David A. Carmel as head of immunotherapy. He will be responsible for leading the company’s collaborative efforts with Memorial Sloan-Kettering Cance Center (MSK) to develop and commercialize allogeneic T-cell therapies for the treatment of certain cancer and persistent viral infections.

The company also appointed Eric Dobmeier to its board of directors. Dobmeier is the CFO of Seattle Genetics

Atara Biotherapeutics stock performance

Over the past 52 weeks, the shares of Atara Biotherapeutics traded between $9.66 and $49.38 per share. The company gained more than 349% in stock value over the past year. It has approximately $1.16 billion in market capitalization. The company’s stock closed at $47.88 per share on Monday.

Baupost Group’s stake in other biopharmaceutical companies

Baupost Group has investments in other biopharmaceutical companies. It owns more than 3,013,848 shares of Kindred Biosciences and 6,061,228 shares of Theravance Biopharma.

Kindred Biosciences is a development-stage biopharmaceutical company focused on developing treatments for pets.

Theravance Biopharma is focused on the discovery, development and commercialization of small molecule medicines across a number of therapeutic areas including bacterial infections, central nervous system (CNS)/pain, respiratory disease, and gastrointestinal (GI) motility dysfunction.

Baupost Group also owns 5,367,300 shares of Forward Pharma, which is focused on advancing the proprietary formulation of dimethyl fumarate for the treatment of multiple sclerosis and other immune disorders such as psoriasis.

In addition, Baupost Group also owns 1,735,218 shares of Paratek Pharmaceuticals, a specialty pharmaceutical company focused on the development and commercialization of therapeutic products in the field of neuroscience.