David Tepper's Appaloosa just dropped about $1 billion on 4 pharma stocks

David Tepper's Appaloosa went big on pharma stocks in the fourth quarter.

The fund took big new positions in Teva ($183 million), Pfizer ($156 million), and Mylan ($125 million) in the final three months of the year, according to a 13F filing. They were the fund's biggest new positions in the period.

In addition, Appaloosa raised its stake in Allergan by 250%, increasing its position by around 3 million shares to a stake worth $894.9 million. The additional shares are worth around $660 million, and Allergan is now the firm's top holding.

The combined investment in the three new pharma positions and the increased Allergan stake adds up to around $1 billion.

The quarterly filing, called a 13F, lists the long stock positions of investment firms. The positions are current as of 45 days ago, so it is possible that Appaloosa has since changed its positions.

Bloomberg analyzed the data based off of a regulatory filing that the firm filed February 14. According to the 13F, Appaloosa's biggest moves in the fourth quarter were:

• A new position in Teva valued at $183.2 million
• A new position in Pfizer valued at $156.2 million
• A new position in Mylan valued at $124.9 million
• Appaloosa increased his position in Allergan to $894.9 million