Dive Brief:

• Amazon founder/CEO Jeff Bezos edged past Microsoft founder Bill Gates, billionaire business magnate, investor and philanthropist Warren Buffett and Facebook founder Mark Zuckerberg to become the world's richest person, as of Wednesday, according to Bloomberg's "billionaire tracker."

• The 53-year-old now enjoys a net worth of $106 billion, by Bloomberg's measure, as the value of Amazon's shares added to a 12-month increase that's seen its market value rise by nearly 57%, Bloomberg reports. 

• Amazon on Wednesday noted how many other businesses are sharing its boom, announcing that more than 300,000 U.S.-based small and medium-sized businesses started selling on Amazon last year, and that its Fulfillment by Amazon program shipped "billions of items" for those sellers, according to a press release emailed to Retail Dive.

Dive Insight:

Bezos' slot at the top of Bloomberg's list of billionaires makes sense, considering Amazon's sales and growth. Earlier this year, Morgan Stanley analyst Brian Newark said that Amazon is on pace to become one of the first-ever $1 trillion companies by the end of this year, and that its many high-margin business operations could push its stock to $2,000 per share. 

Key to Amazon's growth and reach is a vast assortment — and key to that "endless aisle" is its marketplace — half of the items sold on Amazon worldwide are from small and medium-sized businesses that offer their products there. During the holidays, customers ordered more than 1 billion items from smaller third-party sellers, with more than 140 million items ordered between Thanksgiving and Cyber Monday, Amazon said.

In 2017, the number of small businesses selling on Amazon that reached over $100,000 in annual sales increased by 40% to 140,000, according to the release. (That's even more than last year, when the company announced a 30% increase, an Amazon spokesperson said in an email to Retail Dive.)

"More and more small and medium-sized businesses are choosing to join the Amazon Marketplace and sell right alongside Amazon to reach customers around the world. Entrepreneurs and small business owners are succeeding on Amazon – they sell half the products that Amazon customers buy, and more than 140,000 small and medium-sized businesses surpassed $100,000 in sales on Amazon in 2017," Amazon Marketplace Vice President Peter Faricy said in a statement.

Amazon isn't just a platform for sales. Along with its fulfillment service that (for a fee) relieves sellers of the headache of storage, packing and delivery, Amazon supports smaller businesses in other ways. Amazon Lending, for example, has loaned more than $3 billion to marketplace businesses since the program started in 2011. Amazon Handmade has also expanded to 10 categories and offers more than one million handcrafted items from thousands of artisans and small business owners across all 50 states and more than 60 countries, the company said.

But it's not all rosy for Amazon's marketplace sellers. In November, as a price war with Walmart appeared to solidify, Amazon slashed prices for goods sold there. While the e-commerce giant made up for some of the price difference itself, it nevertheless complicated things for many of those businesses. Some are turning to Walmart to diversify, as that retail giant pays renewed attention to its own marketplace in an effort to expand its online assortment. 

Many merchants depend on Amazon for more than 80% of sales, and Amazon's dominance has some worried, according to July research from marketplace commerce platform Feedvisor. More than half (52%) are concerned Amazon will take away their privileges, half are worried about high fees, and 45% are scared that Amazon will compete directly with them, Feedvisor found.