LONDON (BLOOMBERG) - Uber Technologies co-founder Travis Kalanick sold about 20 per cent of his stake in ride-hailing company last week.

Kalanick, 43, who was ousted as Uber's chief executive officer in 2017, sold 20.3 million shares worth about US$547 million (S$744.5 million) that were held in a trust, according to a regulatory filing on Friday (Nov 8).

The trades came after a 180-day lockup period restricting insider and early investor sales following May's initial public offering (IPO). They were among the large stake disposals last week that pushed the stock down to an all-time low.

Uber has underwhelmed investors in the public markets so far. The shares have tumbled 40 per cent since the IPO, reducing the San Francisco-based firm's value from almost US$76 billion at its listing to about US$46 billion. They edged up 0.5 per cent to US$27.14 in New York trading on Monday.

Kalanick remains one of tech's richest entrepreneurs. Even after the sale, he still owns 78 million shares in Uber - a 4.6 per cent stake - and has a net worth of about US$3.7 billion, according to the Bloomberg Billionaires Index.

In March of 2018, Mr Kalanick created a fund called 10100, saying in a tweet it would focus on his "passions, investments, ideas and big bets". That month he announced that he was buying a controlling stake in a distressed real estate company called City Storage Systems for US$150 million and installing himself as CEO.

His latest business, CloudKitchens, got US$400 million of funding from Saudi Arabia's Public Investment Fund, which valued the food startup at US$5 billion, The Wall Street Journal reported on Thursday.