Internet phone firm Skype has filed for an initial public offering in the US.
The Luxembourg-based company hopes to raise up to $100m (£63m) in the stock market flotation.
Skype will sell American Depositary Shares - which represent shares in foreign companies - and expects to trade on the Nasdaq index.
Skype's software lets computer and mobile phone users talk to each other for free and make cut-price calls to mobiles and landlines.
The company did not specify when its shares would go on sale, or at what price.
According to the regulatory filing, in the first half of 2010 Skype had 560 million registered users, who logged 95 billion minutes of voice and video calls.
Online auction site eBay bought Skype for $2.6bn in 2005, but sold 70% of the company for $2bn last year.
A group of private investors made up of private equity firm Silver Lake, the Canada Pension Plan Investment Board and Andreessen Horowitz bought a 56% stake.
Joltid, a firm controlled by Skype founders Niklas Zennstrom and Janus Friis, owns a 14% stake.
In its filing, Skype said it made a net profit of $13.1m in the first six months of the year, but warned that it "may not maintain profitability".
The company reported a loss of $417.5m in 2009, thanks largely to legal costs in settling a dispute about the ownership of the technology it uses.
"We may incur net losses again and cannot assure you that we will be profitable in the future or that, if we are, we will be able to maintain profitability," the filing said.