Read this
TLDR: in the first 3 months of 2013 Nexon made:
435 Million USD in revenue.
-287 Million USD Overhead
148 Million USD pure profit, which is 49.3 per month.
But as you can see in this chart NA (all games) only accounted for 3% of revenues for Q1 2013. Which means from NA they profited 4.44 million in Q1 or 1.48 million/per month, or $49,000 per day. Which is still really good in my opinion. Nexon has 14 games so if you divided evenly it would be about $3,500 per day, per game, in pure profits from NA. It may be higher than that for Combat Arms because I'm sure its more popular than lets say...maplestory, social games, mobile games etc..
It's a shame they are making all this money but can't make the necessary improvements we desperately need. When they first launched CA they said it was one of their top priorities to keep the game balanced and that you could not buy wins. The NX guns are so freaking OP these days it appears that has gone out the window.
Bonus: The name of Nexon's Director of Public Relations is Mike Crouch.