The company behind the Angry Birds mobile phone game has been valued at $8.8 billion.
Finnish company Rovio Entertainment, which was started by three students in 2003, is now worth nearly as much as phonemaker Nokia.
Angry Birds, which was made for the iPhone and is available on Facebook, involves players using a slingshot to attack pigs who steal birds' eggs.
The game has been downloaded more than 800 million times since it was launched in 2009 and has now been developed into a 52-episode TV series and a Hollywood movie.
The total number of active monthly users of Angry Birds reached 200 million at the end of 2011, according to a Rovio Entertainment press release.
Rovio said its finances were good enough for a listing after revealing in its first public disclosure of business results that its total revenue for 2011 reached $120m.