Amazon is unstoppable right now.

Jeff Bezos' machine touched $1,500 a share Wednesday for the first time ever. Amazon's (AMZN) stock is up 27% in 2018 even though the broader market is about flat on the year.

The company's market value is now $718 billion, trailing only Apple (AAPL) and Google (GOOG). Amazon recently surpassed Microsoft (MSFT), which is now in fourth place.

Amazon hit $1,000 a share last May and its stock boomed 73% in 2017. That helped Jeff Bezos become the world's richest person, topping Bill Gates. His wealth surpassed $100 billion in November.

Amazon's stock has raced out of the gate this year after reporting stellar earnings earlier this month. The company announced a profit of nearly $2 billion, the largest in its history and the first time it topped $1 billion in a quarter.

Related: Amazon's latest Prime perk: 5% cash back at Whole Foods

The company has muscled into the grocery industry with its Whole Foods acquisition, built a profitable cloud computing business and expanded its physical footprint with bookstores and a new automated convenience store.

Bezos also announced a partnership with Warren Buffett and Jaime Dimon on a venture to fix the health care industry earlier this month.

Amazon won't come as a bargain to investors though.

The company's price-to-earnings ratio, a measure of how expensive its stock is compared to every $1 of earnings, is 323. The S&P 500's average price-to-earnings ratio is 22.

—CNN's Seth Fiegerman contributed to this report.