Tech-focused hedge fund investor Philippe Laffont has major bets on electric vehicles and health-care stocks, according to new securities filings. Laffont's Coatue Management, which also does venture capital investing, had more than $18 billion of stock holdings in its hedge fund arm at the end of December, according to a securities filing released on Monday. Laffont is a former protégé of legendary hedge fund manager Julian Robertson, making Coatue one of the "Tiger Cub" funds. Its biggest holding at the end of the fourth quarter was Rivian — with a stake valued at more than $3 billion. Rivian has proven to be a popular trade for hedge funds in the final months of 2021. Viking Global and D1 Capital also revealed big bets on the electric vehicle stock in their fourth-quarter filings. Additionally, Coatue added to its stake in Tesla , which came in as the fund's second largest holding. Another area where the firm has two major bets is in the vaccine makers. The company cut its position in Moderna during the quarter, but still ended December with more than $1 billion of the stock. Additionally, Coatue built a stake in Pfizer worth more than $600 million. The fund also added to its large stakes in two Big Tech names in Amazon and Microsoft , while more than doubling its bet on chip stock Lam Research . Coatue initiated or closed several smaller positions throughout the quarter. One notable move was buying 900,000 shares of Activision Blizzard . While that position was worth just under $60 million at the end of the fourth quarter, the stock price has since jumped more than 20% because Microsoft announced a deal to buy the video game publisher.