Amazon's market share was dramatically downgraded, and it could be a weirdly good thing for Jeff Bezos

Amazon is America's second biggest company and the most valuable brand on the planet, but its estimated market share was just dramatically cut.

eMarketer reduced its estimate for Amazon's market share of 2019 online sales in the US from 47% to 37.7% after the tech firm published figures on third-party sales.

The downgrade could actually be weirdly good news for Amazon, which is trying to play down its size at a time when potential tech antitrust investigations are looming.

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A new estimate of Amazon's market share reveals that the tech giant is not as dominant as we once thought.

Amazon is the second biggest company in America, with a market cap of $921 billion, and was this week named as the most valuable brand on the planet.

But its estimated share of US e-commerce sales was dramatically cut by eMarketer, which is frequently cited as a reliable source for Amazon's market share.

The research firm downgraded its percentage of 2019 online retail sales in the US from 47% to 37.7%, The Information reported on Thursday.

According to Bloomberg, eMarketer reassessed its estimates after CEO Jeff Bezos announced in his annual letter to shareholders in April that sales from its third-party sellers now make up for more than 58% of the physical gross merchandise sold on Amazon. These sales have grown from $0.1 billion in 1999 to $160 billion in 2018.

“Third-party sellers are kicking our first party butt,” Bezos said.

Bezos was likely highlighting the strong growth of this arm of the business to demonstrate that Amazon isn't only a crusher of retail competition but can be a promoter too. Amazon has frequently been called out as have a leading role in killing off parts of the retail sector, especially brick and mortar stores as it brings more shopping online.

Read more: The FTC is asking Amazon's rivals if they are being crushed by Jeff Bezos' company

It means the revised market share estimate could actually be weirdly good news for Bezos' company, which is trying to play down its size at a time when potential tech antitrust investigations are looming.

Earlier this month, The Washington Post reported that the FTC and Department of Justice have carved up responsibility for any antitrust investigations concerning Amazon and Google. Under this new agreement, the FTC has oversight of Amazon.

“There is something going on in terms of monopoly,” US President Donald Trump said on Monday in reference to potential investigations into Apple, Amazon, Facebook, and Google. “We're going to look at it,” he added.

The main concern for both regulators is that Amazon is so dominant that it's impossible for others to compete. If its market share is seen to be less dominant than we once thought, this should play into its favor.