The company behind Angry Birds lost a fifth of its market value on Thursday after investors saw its first set of earnings since an initial public offering just two months ago.

Rovio Entertainment's third-quarter earnings report delivered what FIM analysts called a "brutal disappointment," sending the shares down more than 20 per cent.

Angry Bird characters Chuck, voiced by Josh Gad (left) and Red, voiced by Jason Sudeikis (right) in a scene from 'The Angry Birds Movie'. Credit:Rovio Animation

FIM said the bad performance was "caused by a strong increase in user-acquisition investments and clearly softer revenue than expected." Rovio spent €22.2 million ($34.5 million) in an effort to draw in new users for its games last quarter, or more than four times the amount it invested a year ago.

That pushed down profitability, with its earnings falling 29 per cent to €6.1 million. Earnings as a percentage of revenue slumped to 8.6 per cent from roughly 17 per cent.