HELSINKI: Angry Birds maker Rovio Entertainment fell short of market expectations for quarterly sales and profit on Thursday, sparking a near 20 percent fall in the Finnish firm?s shares.

Increased marketing costs meant adjusted earnings before interest, tax, depreciation and amortization were flat at 8.6 million euros ($10.2 million) in the third quarter, although sales rose 41 percent from a year ago to 70.7 million euros.

?Costs were surprisingly big but also the number of paying customers lagged expectations,? Hannu Rauhala, an analyst at OP Equities, who has a ?buy? rating on Rovio, said.

?The company has changed a lot in the past years and it is considered as a growth company. The stock is strongly driven by growth expectations,? Rauhala said.

Rovio saw rapid growth after the 2009 launch of the original ?Angry Birds? game, but it plunged to an operating loss and cut a third of its staff in 2015 due to a pick up in competition and a shift among consumers to freely available games.

Rovio?s game titles now include ?Angry Birds 2,? ?Angry Birds Blast?, ?Angry Birds Friends? and ?Battle Bay.?