Shares in the e-commerce giant rose nearly 2% to a high of $2,050.50 in morning trade before slipping back.

Apple reached the same milestone in early August.

Founded in 1994, Amazon is now the world's largest online retailer. Its chief executive, Jeff Bezos, is the world's richest man, with a net worth of more than $160bn.

• How Jeff Bezos took Amazon to the top

Neil Saunders, managing director of GlobalData Retail, said: "To reach a market capitalisation of over $1tn is impressive. To do it in a little over 24 years is extraordinary.

"That Amazon has achieved this demonstrates its dramatic advancement in both the retail and technology sectors, as well as the influence it now wields over large parts of the consumer landscape."

Analysis: Kim Gittleson, New York business correspondent

Like a pesky younger sibling, Amazon might be second to the symbolic trillion-dollar milestone - but when it comes to its rivalry with Apple, it's been quicker to hit nearly every hundred-billion dollar valuation hurdle.

For instance, it took Amazon just 16 days, compared to Apple's 622 days, to go from a market value of $600bn to $700bn, according to the Wall Street Journal.

This acceleration makes sense in a way, because Amazon spent most of its time as a public company reporting losses or negligible profits. Founder Jeff Bezos consistently said he would rather reinvest sales revenue into the company to give it a better, more profitable future.

It's a strategy that seems to have paid off: Amazon reported $2.5bn in profit last quarter, making it one of Wall Street's most profitable companies.

And the future seems bright.

Even more so than Apple, Amazon is in the business of how we'll live in the future.

Although nearly half of every dollar spent online by an American goes to Amazon, e-commerce still makes up just 9% of total retail sales here. And Amazon has also become the market leader in cloud computing, with its Web Services business line consistently beating expectations.

All of this suggests that when it comes to Amazon's growing market value, the best word to describe it might in fact be the name Mr Bezos reportedly initially had planned for the company: relentless.

Amazon reported nearly $53bn in sales in the three months ended in June, with record quarterly profit of $2.5bn.

The firm is expected to account for roughly half of all online shopping sales in the US this year - and nearly 5% of the country's overall retail market, according to research firm eMarketer.

It employs more than 575,000 people, a force nearly the size of Luxembourg's population.

It provides logistics, storage, loans and a selling platform to hundreds of thousands of third-party merchants.

Its profitable cloud computing division, which hosts huge swathes of the corporate world on its data servers, is the industry's global leader.