As pointed out on NeoGAF by user boskee, CD Projekt Red's market cap is over $1.6 billion USD, and that means it's worth more than Capcom.
Boskee also gives some perspective on this information, as Polish energy company Tauron employs 25,000 people and is valued at $600 million less than the developers of The Witcher franchise. This new information also means that CD Projekt Red are the 15th biggest company on the Polish stock exchange as well. As if all this wasn't impressive enough, the studio are also the biggest Polish exporter in IT sector, wtih 95% of revenue generated from outside the country.
As you can imagine, all of this success is most likely down to a number of things - the Christmas period has just been, for instance, and the phenomenally successful Witcher 3 may have been under Christmas trees for many. Also, the Gwent beta and upcoming game Cyberpunk 2077 will no doubt have helped the increase in share value, of which there has been 56% in the last three months.
How big can CD Projekt Red grow?