Amazon.com, Inc.’s (AMZN) CEO Jeff Bezos is making the most from the recent run-up in Amazon’s stock price.

A recent SEC filing indicates that Bezos has sold around 1 million Amazon shares during the first few days of this month, which helped him rake in almost $1 billion. The development comes on the back of the recent announcement Bezos made that he sells $1 billion worth of the stock each year to fund his ambitious Blue Origin space trip venture. (See also: Bezos Selling $1 Bn Amazon Stock Every Year to Fund Blue Origin)

Bezos’ Blue Origin plans to offer paying customers an 11-minute ride in space and competes with Richard Branson’s Virgin Galactic and Tesla Motors Inc.’s (TSLA) founder Elon Musk’s SpaceX, which expects to offer tourists a ride around the moon by next year.

This is the most Bezos has made on a single sale ever, courtesy of more than 25% gain clocked by Amazon stock in the year 2017 till date. Shares of Amazon hit a record high of $954.40 apiece on May 1. The sale of shares, spread across the following three days, was executed at price ranging from $935 to $950 per share. Bezos still owns around 79.9 million shares of Amazon, representing around 17% of the company, though his stake has come down from the 83 million shares he owned at the end of 2015.

Bezos is not new to selling Amazon shares. He made two big sales last year, in May and in August, which grossed around $1.4 billion. The steady growth in Amazon’s ecommerce business and significant profits reaped by its cloud-computing division have helped Bezos scale up the ladder in the ranks of the world’s richest individuals. According to the Bloomberg Billionaires Index, Bezos now stands at number three position behind Microsoft Corp.’s (MSFT) co-founder Bill Gates and Spanish entrepreneur Amancio Ortega Gaona. (See also, Amazon's Top Earner Is Not CEO Jeff Bezos)