Shares in Snap, owner of messaging app Snapchat, began trading on the US stock market on Thursday.
At the close of trade shares were $24.48 each, a jump of more than 40%.
The flotation valued the company at $17 a share, or $24bn in all, although Snap has never made a profit.
The firm’s inital public offering (IPO) is the biggest for a US tech firm since Facebook in 2012 and will turn the company’s founders, Evan Spiegel and Bobby Murphy, into multi-billionaires.
Snapchat, which is especially popular with teenagers, allows users to send images and messages which then vanish.
The company’s losses widened last year, and user growth is slowing down in the face of intense competition from larger rivals such as Facebook.
Despite the challenges in converting “cool” into cash, Snap’s valuation is the richest for a US tech flotation since Facebook in 2012.
At the beginning of February Snap’s formal announcement to regulators of its plans revealed that the company had revenue of $404m last year, but made a loss of $515m.
Unlike in most listed companies, people who buy the floated shares in Snap will not get any voting rights.
Some analysts argued the company was overvalued.
“Snap is a promising early stage company with significant opportunity ahead of itself.
“Unfortunately, it is significantly overvalued given the likely scale of its long-term opportunity and the risks associated with executing against that opportunity,” wrote analyst Brian Wieser from Pivotal Research in a note. He gave it a “sell” rating.
Others were more positive.
Before the trading debut, Jordan Hiscott, chief trader at Ayondo Markets, said: “What sets it apart from other messaging apps like WhatsApp for me is the innovative features built into the app’s interface, such as the lenses function.
“A pertinent point in the company’s S1 filing for the IPO is that it doesn’t call itself a messaging service, but a camera company.”
“This seems to be an intentional move to differentiate it from Facebook and Twitter and the success and failure of their respective IPOs, which in my view, is very clever.”