Investors who buy Amazon.com stock, which trades at a sky-high multiple, are taking a big risk, one analyst told CNBC on Monday.
"It's not like Amazon's not going to continue to grow quickly or gain share, but the problem is are you willing to pay 85 times price to earnings or 24 times EBITDA?" said Dan Niles, chief investment officer at AlphaOne Capital partners.
Amazon's business is getting hit by the law of large numbers as the revenue growth rate to its large ecommerce market share decelerates, Nile told CNBC's "Squawk on the Street."
"Investors are OK paying a high multiple if you are thinking, 'Oh, the opportunity is open ended,'" he said. "But at this point,you've seen the growth rate cut more than in half. And I think the next thing that's probably going to get affected is profit growth, which is going to be the really big problem in the future."
"You're taking a big risk with that multiple, and ... the way you really need to think about investing is risk reward," he continued.
Niles also weighed in on the Apple vs. Samsung competition for great smartphone market share. Last year, Samsung picked up market share while Apple's portion of the smartphone market remained nearly flat.
"When the iPhone first came out, it was the only one that could do what it did," he said. "Today, I would argue that Samsung makes a better phone."
(Read More: Samsung Takes on Apple With New Galaxy S4)
Although he didn't go so far as BlackBerry CEO Thorsten Heins did in labeling the iPhone as "dusty," Niles did say it's not the best phone on the market.
One challenge for Apple is that its phones are sold in fewer countries than the Samsung Galaxy. The iPhone's higher price poses another problem. Near term, Niles does not think a lower-priced phone is in the cards for Apple.
But he did predict it will launch something in the TV space before year end, a product that he said hopefully will not be just a set-top box or an Apple TV improvement but rather an actual television. He also said he thinks the company will issue a buyback or dividend increase at some point soon. (Read More: Apple to Make 'Dramatic' Move: Pro)
—By CNBC.com's Katie Little; Follow on Twitter
Disclosure information was not available for Dan Niles.