Business Insider/ Mike Nudelman
Tiger Global bought 2.44 million shares of Amazon, bringing its stake to more than 3.19 million shares, according to the fund's 13F filing.
The share price low for the quarter was $437.39, meaning the new shares must have cost at least $1.1 billion.
On September 30, the last day of the third quarter, Amazon's shares were trading at $511.89, valuing Tiger Global's stake at $1.63 billion.
So far, Tiger Global's bet has paid off.
The stock closed at $647.81 per share on Monday, valuing the position at $2.1 billion.
Amazon is Tiger Global's second largest stock position. In the second quarter, Tiger Global took a massive stake in Netflix. The fund still held that position in the third quarter.
Hedge funds only have to disclose their long equity holdings every quarter in these filings. What's more, the filings aren't published until 45 days after the end of the quarter, so it's possible funds could have traded in and out of positions.
Disclosure: Jeff Bezos is an investor in Business Insider through hispersonal investment company Bezos Expeditions.