Kodansha Comics has a new CLAMP series and is launching two new omnibus series.

Kodansha will launch xxxHolic: Rei, the newest manga from CLAMP, late in 2013.  The story of Yuko the space-time witch is currently being serialized in Young Magazine, and the first tankoubon has yet to be released in Japan.
 
Kodansha is launching two three-volume CLAMP omnibus series in 2014: xxxHolic Omnibus, launching in March, and Tsubasa: Reservoir Chronicles Omnibus, launching in August.  Both properties were in the ICv2 Top 25 Manga Properties as recently as 2010, xxxHollic in Q1 (see "Top 25 Manga Properties--Q1 2010"), and Tsubasa for the full year (see "Top 25 Manga Properties--2010").
 
--Nathan Wilson