The size of the CE varies in proportion to the size of the MAGTF. A Marine Expeditionary Force has a MEF Headquarters Group, approximately the size of a regiment. A Marine Expeditionary Brigade holds a battalion-sized MEB Headquarters Group. The various Marine Expeditionary Units command a company-sized MEU Headquarters Group. Generally, MEF postings are permanent, while MEBs and MEUs rotate their GCE, ACE, and LCE twice annually.