SKYPE SA, the Internet calling service that was controlled until last year by eBay Inc, yesterday filed for a United States initial public offering.

Luxembourg-based Skype tentatively put the value of the offering at about US$100 million, but that's a rough estimate only used as a basis for the filing fee for the US Securities and Exchange Commission.

Skype did not say when its shares would go on sale, or at what price. It expects to list on the Nasdaq Stock Market under an unspecified symbol.

EBay sold 70 percent of Skype for US$2 billion to an investor group led by private-equity firm Silver Lake, the Canada Pension Plan Investment Board and Andreessen Horowitz.

The group owns 56 percent of the company.

The remaining 14 percent is owned by Joltid, a firm controlled by the founders of Skype, Niklas Zennstrom and Janus Friis. EBay kept a 30 percent stake.

Friis and Zennstrom sold Skype to eBay for US$2.6 billion in 2005 and left the company in 2007.

Between November 19, when it became independent of eBay, and December 31, Skype lost US$99.7 million on US$92.4 in revenue, according to the filing with the SEC.

Calls between Skype users are free. The company makes most of its money from calls Skype users place to landline and cellular phones.

Skype said a portion of the IPO shares will be made available to its customers, "based on the nature and extent of their relationship with Skype."

Goldman Sachs, JPMorgan and Morgan Stanley will lead the offering.