Shutterfly, an Inc. 500 company and one of the first online photo services, is keeping tight-lipped in response to rumors of a planned sale or initial public offering.

According to anonymous sources cited on Monday by The Wall Street Journal, either deal could net the Redwood City, Calif.-based company between $400 million and $500 million. Shutterfly did not return calls for comment on Tuesday.

The report also claims that the company has made several moves over the past year to prepare for a sale or IPO, such as hiring executives with experience in IPOs and mergers.

Shutterfly was founded in 1999 with an initial investment by Jim Clark, founder of Netscape Communications and Silicon Graphics. The online service allows customers to store and share photographs, while offering prints and other gift items.

In 2005, the company ranked No. 170 on the Inc. 500, an annual list of the nation's fastest growing small businesses. In 2004, it posted annual revenue of $54 million and grew at a rate of 627% over the previous three years.