Popular online payment service PayPal Inc. filed plans Friday to sell its stock in an initial public offering that will try to overcome investors' recent disdain of unprofitable Internet companies.

The Palo Alto-based company didn't set an offering price or the number of shares to be sold in the IPO, but said it hopes to raise up to $80.5 million in a prospectus filed with the Securities and Exchange Commission

PayPal is pursuing its IPO in a frosty climate. With Wall Street turning a cold shoulder to tech companies, only three Silicon Valley companies — Align Technology Inc., Riverstone Networks Inc. and Loudcloud Inc. — have gone public so far this year. Sunnyvale-based Loudcloud, chaired by Web browser pioneer Marc Andreessen, pulled off the last Silicon Valley IPO at $6 per share in March, and its shares are now trading at $1.12.

Securities laws prevented PayPal executives from discussing its IPO Friday, but the company is apparently hoping investors will be wooed by the rapid growth of its service in its 2 year history.

As of Sept. 1, PayPal had 10 million registered users and processed online transactions totaling $747 million in the three months ended June 30, according to its prospectus.

The company creates "digital cash" by accepting credit card payments from its users and then delivering the payments to a designated recipient. The recipient then can either get real cash or leave all or part of the balance in a PayPal account for future transactions.

The system doesn't require PayPal to spend much to attract business. In the first half of this year, for instance, PayPal spent just $48,000 on marketing and promotion.

The service is particularly popular among small businesses and sellers on eBay's auction site because it guarantees that they will be paid for merchandise, frequently at a lower cost than the merchant fees imposed by major credit cards.

PayPal typically charges transaction fees ranging from 2.2 percent to 2.9 percent of the sale, plus 30 cents.

That hasn't been enough to make PayPal profitable. The company has lost $231 million since its inception and management warned in the prospectus that the red ink is expected to continue at least through the rest of this year.

But the company is narrowing its losses as its revenues climb. During the first six months of this year, PayPal lost $56.9 million on revenue of $34.2 million compared with a loss of $70.6 million on revenue of $3.3 million at the same time last year.

PayPal is run by one of its co-founders, Peter Thiel, 33, a former securities lawyer. Other major shareholders in the company include another co-founder, Elon Musk, and Silicon Valley venture capital firms Sequoia Capital, Nokia Ventures and Clearstone Venture Partners.

The IPO is being underwritten by investment bankers Salomon Smith Barney, Robertson Stephens and William Blair & Co.