Alibaba, in a conversation with Fortune, countered with a straightforward explanation: China’s cohort of online shoppers is massive and prolific in their purchasing, and Alibaba’s marketplace is their favorite place to shop.

Alibaba (BABA) skeptics’ argument essentially boils down to this: The huge numbers that the company reports are simply too big to believe. How could it be possible that a company that was virtually unknown to Americans a few years ago, based in an emerging market, dwarfs U.S. stalwarts—reporting more customers than Amazon (AMZN) and more deliveries than UPS (UPS), while growing faster than Facebook (FB) and Google (GOOG)? As Hempton put it, “This suggests a level of shopping in China that puts the US, Europe and most of Asia to shame.”

In particular, Hempton fixated on Alibaba’s claim that on its peak shopping day in 2014, known as Singles’ Day, the company received—and shipped—278 million orders. That is more than 17 times the 16 million orders that Amazon received on Cyber Monday (the U.S. e-commerce bonanza following Thanksgiving). Hempton doubted that Alibaba had enough staff or logistics resources to pack and move all those orders in one day.

But while Alibaba’s numbers seem too good to be true, there’s another possibility: They’re actually just that good. Several Fortune readers wrote in or tweeted to defend Alibaba’s figures and explain why Chinese e-commerce really “is on a whole different level compared to e-commerce anywhere else.” One reader wrote: “Regarding Chinese purchasing power, just Google ‘Chinese tourist spending in California.’” (We Googled; it leads to a statistic that Chinese travelers spend $6,000 to $7,200 per U.S. visit—which makes them bigger spenders than any other tourist demographic.) Another reader pointed us to a documentary depicting the army of Chinese couriers who deliver Alibaba’s and other e-commerce packages across China.

Fortune asked Alibaba to rationalize its figures, and to address the seeming disconnect among its nonbelievers. Was it possible that the scope of Alibaba is so vast that American investors are struggling to wrap their heads around it? In short, yes, according to Alibaba spokesperson Bob Christie, who’s based in the U.S.

“You just can’t compare apples to oranges,” Christie said, referring to the U.S. and Chinese marketplaces. He then put it in terms that many Wall Streeters could relate to: “You and I can go down to the corner store and pick up toothpaste at 2 in the morning,” he said. “That is not an option in China. The only way to get it is to go on a platform and have it delivered to your house.”

Then Christie broke it down, saying, “Just to give you some numbers to blow your mind”:

• China has a population of 1.4 billion people. That’s more than a billion people more than the 321 million people in the U.S.
• There are 668 million people who use the internet in China—or more than double all the people in the U.S.
• Last year, Alibaba represented 86% of shopping done on a mobile phone in China.
• Alibaba has 367 million active users (defined as someone who purchased something in the last year). In other words, it has more customers than the entire populations of the U.S. and Canada combined.
• On average, those active buyers purchased 58 packages per year—or more than one per week. (And each package could contain more than one item.)
• Alibaba has more than 10 million active sellers on its marketplaces. By comparison, Amazon reported more than 2 million sellers on its marketplaces worldwide (representing 40% of goods sold on the site).
• On last year’s Singles’ Day, celebrated on Nov. 11, Alibaba grossed $9.3 billion in sales—more than U.S. e-commerce sales on Black Friday ($1.5 billion) and Cyber Monday ($2 billion) combined. (Singles’ Day was also 41% bigger by sales volume than U.S. online shopping during the 5-day spree between Thanksgiving and Cyber Monday, which raked in $6.6 billion).
• Alibaba, through its 15 courier partner companies, delivers an average of 30 million packages per day. UPS, by comparison, delivers an average of 18 million packages per day, and delivered 35 million packages on its peak delivery day in 2014.
• On an average day, there are more Alibaba packages delivered than the United States Postal Service delivered on its busiest day ever: December 22, 2014 (the Monday before Christmas) when the USPS delivered 28.2 million packages.
• Alibaba uses more than 1.5 million delivery personnel—a logistics army larger than UPS (435,000 employees) and FedEx (FDX) (300,000 employees) combined. (Alibaba doesn’t directly employ any of the 1.5 million people delivering its packages; the couriers are employees of the 15 delivery companies that are Alibaba’s partners and make up its logistics network. Alibaba itself has 34,500 employees.)
• In China, Alibaba is the only e-commerce retailer to have an official Apple (AAPL) store on its own online marketplace (on its Tmall.com site)—meaning it can accept pre-orders for iPhones, for example, when other online retailers can’t.

Alibaba’s spokesperson also offered a couple of other statistics that might explain why its investors have trouble understanding its business: 80% of Alibaba’s shareholders are located in the U.S., and 90% are outside of China, Christie estimates. And few Americans have ever actually shopped on Alibaba, or particularly its Tmall.com marketplace, which is in the Chinese language. “Our investors have no experience of actually using the products,” Christie said. “If you can find someone who has in the United States, I guarantee they’re Chinese and they’ve moved here,” Christie said.

Of course, mammoth size today doesn’t guarantee Alibaba a bright future. The suspicions about the company’s numbers came at a particularly sensitive time, as Alibaba just marked its one-year anniversary on the New York Stock Exchange on Saturday, enabling the company’s major shareholders to begin selling large chunks of stock that had been under lockup restrictions; the stock has been tumbling ever since, and is down more than 42% since the beginning of this year. Investors continue to be wary, not least because the Chinese economy appears to be slowing down. If that happens, it could mean that as big as Alibaba’s numbers are today, they might not get any bigger.

For more about China’s tech sector, watch this recent episode of Fortune’s “Tech Debate”: