Fast-growing daily deal website Groupon Inc. on Thursday filed to go public, the first step what will be one of the year's most hotly anticipated initial public offerings.

Groupon estimated it would raise $750 million from new investors when it goes public, confirming weeks of speculation. It said it hadn't decided how many shares to offer or how to price them.

The filing also gave the first peek at Groupon's finances. The company has grown to $645 million US in revenue in the first quarter from just $3.3 million in the same quarter two years ago, although it has sacrificed profits in the name of growth.

Groupon now has 83 million subscribers.

Groupon's move follows an IPO last month by social-networking site LinkedIn Corp. that valued that company at $9 billion  by the end of its first day of trading.

The company offers its subscribers the chance to purchase daily discounts targeted to their city and preferences. For example, a subscriber might pay $20 for a $40 gift certificate to a spa, restaurant, car wash or yoga studio.