Snap, owner of the Snapchat messaging app popular with teenagers, is to sell its shares on the US stock market. The California-based tech firm, which allows users to send images and messages that vanish within seconds, is set to be one of the major US share listings of recent years. The flotation is expected to value the business at between $20bn and $25bn, although Snap has never made a profit. It will turn the company's founders into multi-billionaires. Snap wants to raise $3bn through the share sale, a small percentage but one that will set the market price for the rest of the company. The company began in 2011 when co-founder and chief executive, 26-year-old Evan Spiegel, was still at university. Mr Spiegel and fellow founder Bobby Murphy, 28, have stakes in Snap that would be worth about $5bn. Snap now has nearly 160 million daily users and last year revenues grew by nearly 600%, the listing documents revealed. Most of Snapchat's revenue comes from advertising, and it is seen as an appealing way for companies to reach young people, with over half of its users aged between 13 and 24.