An Omnicom spokesperson confirmed the departure. Anonymous sources including a senior ex-OMD staff member cited the Omnicom-Publicis merger as a reason for Lim's resignation.
Lim, who joined OMD in October 2010 from Mindshare, reported to Doug Pearce, Omnicom Media Group's China CEO. Contacted this afternoon, Pearce said Lim is leaving for her own reasons, and that her decision had nothing to do with the Omnicom-Publicis merger.*
Lim is reportedly looking for opportunities outside China, partly for the sake of her children’s education, according to a source.
Campaign was unable to reach Lim directly.
* Update, 3 pm: Added comments from Pearce.