  S5 0716+714 is a well known BL Lac object, one of the brightest and most
active blazars. The discovery in the Very High Energy band (VHE, E > 100 GeV)
by MAGIC happened in 2008. In January 2015 the source went through the
brightest optical state ever observed, triggering MAGIC follow-up and a VHE
detection with 13{\sigma} significance (ATel 6999). Rich multiwavelength
coverage of the flare allowed us to construct the broad-band spectral energy
distribution of S5 0716+714 during its brightest outburst. In this work we will
present the preliminary analysis of MAGIC and Fermi-LAT data of the flaring
activity in January and February 2015 for the HE (0.1 < HE < 300 GeV) and VHE
band, together with radio (Mets\"ahovi, OVRO, VLBA, Effelsberg), sub-millimeter
(SMA), optical (Tuorla, Perkins, Steward, AZT-8+ST7, LX-200, Kanata), X-ray and
UV (Swift-XRT and UVOT), in the same time-window and discuss the time
variability of the multiwavelength light curves during this impressive
outburst.
