A corner form panel used in an insulating concrete form system includes a hinged corner web member at least partially embedded in each of two segments of the form panel. The hinged corner web member enables the two segments to rotate with respect to each other, so that the form panel can be opened to a flat configuration for shipping, and folded into a corner configuration at the jobsite. Both inside and outside corner panels may be provided, and may use different hinged corner web members. The corner web member may include features for connecting the inside and outside corner panels, to reinforce the resulting form unit.