Jeff Bezos sold nearly $350 million worth of Amazon.com (AMZN) shares after the stock hit a record high on Monday, marking his first sale of the company's stock this year, Bloomberg reported Wednesday.

The sale represented a small portion of the up to 15 million shares, worth more than $4 billion, that Bezos disclosed he planned to sell earlier this week, the report said.

Even after the sale, Bezos remains Amazon's largest shareholder with an 8.16% stake, according to Bloomberg. The report said his wealth has risen $38.7 billion this year to $292 billion as Amazon shares have gained 18%.