Shares of Airbnb Inc more than doubled in their stock market debut on Thursday, valuing the home rental firm at just over $100 billion in the biggest US initial public offering of 2020 and capping a bumper year in which investors flocked to tech stocks.

Airbnb opened at $146 on the Nasdaq, far above the IPO price of $68 per share that raised $3.5 billion for the company. The stock hit a high of $165 and closed at $144.71.

The IPO is the culmination of a stunning recovery in Airbnb's fortunes after the firm's business was heavily damaged by the COVID-19 pandemic earlier this year.

But as lockdowns eased, more travelers opted to book homes instead of hotels, helping Airbnb post a surprise profit for the third quarter. The San Francisco-based firm also gained from increased interest in renting homes away from major cities.

"I don't think this summer too many people expected to see an Airbnb IPO this year," said Airbnb Chief Executive Brian Chesky.

"We were planning on going public, we put our IPO on hold and this has been the most unbelievable journey. It's been quite a comeback for our hosts and for what I hope will be travel," added Chesky, whose Airbnb stake is now worth around $11 billion.

Founded in 2008 as a website to take bookings for rooms during conferences, Airbnb's listing was one of the most anticipated US IPOs of 2020, which has already been a record year for stock market listings.

At the start of trading on the Nasdaq, Airbnb had a market capitalization of $86.5 billion, eclipsing that of online travel agency Booking Holdings Inc and hotel chain Marriott International Inc.

Including securities such as options and restricted stock units, Airbnb's fully diluted valuation came to $100.7 billion, more than five times the $18-billion Airbnb was valued at in a private fundraising round in April at the outset of the pandemic. Airbnb's worth was pegged at $31 billion in its last pre-COVID-19 private fundraising in 2017.