** Renewable energy storage provider Fluence Energy FLNC.O shares up 0.2% at $21.32 in premarket trading after $420 mln secondary offering priced

** Arlington, Virginia-based FLNC early Weds announced sale of 20 mln shares by certain controlling stockholders at $21

** Offering price represents 1.3% discount to stock's last close

** FLNC shares tumbled 15.7% on Tues after co commenced the offering

** Prior to offering, AES AES.N and Germany's Siemens SIEGn.DE each owned ~51.5 mln shares, and Qatar Investment Authority held 14.7 mln shares, per the prospectus

** Barclays, Goldman Sachs, JP Morgan joint bookrunners for offering

** Through Tues, FLNC stock up 68% over the past week, putting it up 7.6% YTD

** Avg rating of 20 analysts is "hold"; median PT $16, according to LSEG data