Amazon Inc. (AMZN) has seen its market value jump seven-fold in just five years, becoming the second U.S. corporation to surpass the $1 trillion mark briefly on Tuesday and reaching that milestone nearly twice as fast as smartphone maker Apple Inc. (AAPL). Now, bulls see at least five forces which could double the value of the e-commerce and cloud-computing giant to reach $2 trillion, including its cloud business, surging ad sales, opening of physical stores, artificial intelligence (AI) push and health care business, according to a detailed story by CNBC.

Amazon's Meteoric Stock Growth

Company Five Year Return
Amazon 618%
Apple 257%
Alphabet 187%
Facebook 303%
Netflix 800%
S&P 500 75%

While both Amazon and Apple have grown their businesses by improving their core offerings, the Seattle-based online retailer has accelerated its growth by diversifying into new growth markets and expanding into traditional industries such as brick-and-mortar grocery and apparel. Apple, which has recently doubled down on software and services to hedge against declining smartphone unit sales, took 38 years to reach $1 trillion, compared to Amazon's 21-year run. (Fore more, see also: Amazon to Hit $2.5 Trillion by 2024: MKM.)

5 Key Drivers of Amazon's Growth

Cloud business
Surging ad sales
Opening of physical stores
Artificial intelligence

Booming Cloud Business

Amazon's burgeoning cloud business, Amazon Web Services (AWS) has been touted as a main driver of the firm's next stage of growth. The segment is on track to generate $25 billion in revenue over the next 12 months, having securing sales growth near 50% in Q2, as noted by CNBC. Its profitability, which accounts for 65% of Amazon's total operating income, makes it easy for the deep pocketed tech titan to dabble in new markets with high upfront costs. 

Expansion into Healthcare and Pharmacy 

Amazon's push into the health care space and $450 billion U.S. pharmacy market is already well under way. Jeff Bezos' "everything store" has teamed up with Buffett's Berkshire Hathaway Inc. (BRK.A) and Jamie Dimon's JPMorgan Chase & Co. (JPM) to create a joint health care venture aimed at reducing and simplifying healthcare costs for employees. The new healthcare venture has been building out its executive team with the most recent hire of Jack Stoddard, former general manager for digital health at Comcast Corp. (CMCSA) as Chief Operations Officer. In June, the retail behemoth announced its $1 billion takeover of online pharmacy startup PillPack, granting it pharmaceutical licenses in nearly every state upon the deal's closure. 

Ad Growth, AI Leadership

The third growth driver highlighted by CNBC for the FANG stock is its accelerating ad business, which recently surpassed $2 billion in quarterly sales. While a majority of Amazon's ad revenue comes from selling product search results, bulls see the firm expanding ads into voice, Prime Video, and other platforms as it uses its mass of consumer data to target shoppers. 

CNBC also touted Amazon's leadership in the AI space, leveraged across AWS, Alexa, the Amazon Go store and other key projects. Bulls see Amazon turning Alexa into a large developer platform, while reaping returns from a voice technology market expected to triple to $18 billion by 2023. 

Physical Retail Presence

Lastly, CNBC cited Amazon's bet on the brick-and-mortar space, solidified by its $13.7 billion acquisition of Whole Foods Market Inc. and its $22 billion in additional future contract obligations. The organic grocery chain has provided Amazon with hundreds of physical locations to sell its branded products, as well as other potential additions like pharmacy locations. Whole Foods has served as an avenue to ramp up its omnichannel platform and bolster businesses such as Fresh delivery, while enhancing the customer experience with features like AI-powered cashiers. 

It's important to note that some experts say Amazon's stock is already way too stretched, indicating that further gains are unlikely. In a note to clients on Tuesday, equity strategist Matt Maley of Miller Tabak warned that Amazon is in for a pullback as the stock trades at a 136% premium to its 200-week moving average. Gina Sanchez, CEO of Chantico Global, told CNBC's "Trading Nation" that investors should be concerned over Amazon's multiple at 159.71 times trailing earnings, compared to the broader market at roughly 21 times, calling it "off the charts." (For more, see also: Cisco a Better Bet Than Apple, Amazon, Tech Giants: Piper Jaffray.)