The STALKER facebook page doesn't seem to agree with this:
http://www.facebook.com/officialstalker"In view of the rumors appearing in press, we find it necessary to inform that GSC Game World and Sergey Grigorovich remain to be the sole owners of all the intellectual property rights to the S.T.A.L.K.E.R. game series and the brand overall, including all the trademarks, the game universe, the technology etc. This can be easily verified with the trademark services online.
From time to time news on the S.T.A.L.K.E.R. brand purchase by this or that company appear over the Internet. We relate such a keen interest in the brand to its exceptional popularity. Even the purchase of rights to create a “Roadside picnic” book-based game by a small publisher is presented as the continuation of S.T.A.L.K.E.R. franchise. We have doubts regarding the mentioned product by bitComposer (the publisher of S.T.A.L.K.E.R.: Call of Pripyat on some territories), since the latter has significant debts in terms of fulfilling the obligations under the existing contract between our companies."