Active player days rose to 5.4m, an increase of 59%, while average revenue per daily active user grew 91% to $15m.
Dermot Smurfit, CEO of GAN, said the company experienced a "better-than-expected" third quarter and pointed to the demand for US sports betting during the seasonally weaker summer months as an explanation.
From 11 to 13 September, GAN saw its share price jump from £0.68 ($0.83) to £0.88. It has however, declined since a peak of £0.91 on 23 September; it currently sits at £0.79.
Smurfit said: "The exceptional growth rate year-on-year is exaggerated by mass-market US online sports bettors in New Jersey crossing over into the online casino before, during and after sports events and the faster-than-anticipated ramp-up of Pennsylvania online gamblers."
The CEO also said GAN sees more online gamblers in Pennsylvania than in New Jersey.
