These certificates are issued for free by the EU and companies trade them between each other, just to be able to pollute more. The day price at the moment they where stolen was 2,5 EUR a piece.
It makes makes no sense to me at all. If I understood the article correctly the certificate does not impose CO2-emission limitations to companies. So basically it is normal that the EU would ask nothing for this certificate, because it does not give you any privileges.
Isn't it kind of weird then that a company is ready to pay 2,5 EUR for something that actually doesn't do anything for your company? The funny part is then that people start stealing these things. It kind of remind me when I was at school and saw kids fight over little plastic disks called flippo's.