Radio vs. X-ray luminosity for UCDs including DENIS 1048-3956 (green larger symbols connected by the vertical line), PC 0025+0447, and DENIS 1228-1547 (both also shown in green and larger). The Benz-Güdel-relation for more massive late-type stars is represented by the black solid line and its extrapolation to low luminosities is dotted. The lowest observed emission level of each object is shown as a circle. Two groups with distinct flaring behavior in the radio (orange with asterisks for the flares) and X-ray (red with star symbols for the flares) bands are identified. Objects that cannot be assigned to any of the groups (yet) are shown in black.