** Vir Biotechnology's VIR.O shares down 10% premarket at $9 after $150 mln follow-on priced

** San Francisco, California-based firm late Weds announced ~17.6 mln shares at $8.50, a 15% discount to last sale

** VIR shares finished up ~5% at $10 on Weds following 28% gain on Tues after co posted Q4 rev beat and said it's collaborating to develop its prostate cancer experimental drug with Japan's Astellas 4503.T

** After the bell Tues, co announced $200 mln stock offering

** It intends to use net offering proceeds to fund its portion of global clinical development costs, and potential portion of commercial launch costs for the drug, VIR-5500, under the Astellas agreement, among other purposes, per the offering prospectus

** Goldman Sachs, Leerink, Evercore and Barclays joint bookrunners

** Co has ~139.5 mln shares outstanding

** Through Weds, stock up 66% YTD

** All 10 analysts covering VIR are bullish and their median PT is $18, per LSEG data

(Lance Tupper is a Reuters market analyst. The views expressed are his own)

((lance.tupper@tr.com 1-646-279-6380))