Now it's Amazon's turn at the top.
The 24-year-old company surpassed Microsoft as the world's most valuable public company on Monday, closing the trading day with a market value of $796.8 billion. Microsoft, which just passed Apple to take over the top spot a little over a month ago, is worth $783.4 billion.
It's been a bumpy ride up the charts. Amazon's market capitalization topped $1 trillion in September, but a late-year stock market collapse resulted in the worst quarter for the shares since the 2008 recession. Nevertheless, after rallying in three of the first four trading days of 2019, Amazon is No. 1.
There are a number of reasons why investors remain bullish on the stock, but it mostly comes down to avenues for expansion.
"Despite its current massive size, we see Amazon's opportunities as mostly unconstrained based on a successful track record of capitalizing on consumer and IT department spending," Brian Wieser, an analyst at Pivotal Research Group, wrote in a note to clients on Monday. He initiated coverage with a "buy" rating and a target price of $1,920, which represents an 18 percent increase from the current price.
Amazon rose 3.4 percent on Monday to $1,629.51, and the stock is up 8.5 percent in 2019.
Here are five topics that are exciting Amazon investors: