Vir Biotechnology tumbles on planned stock sale

** Vir Biotechnology's VIR.O shares tumble 15% to $10.30 in extended trading as it seeks equity raise

** VIR announces stock offering without disclosing deal size

** Leerink, Morgan Stanley and Evercore bookrunners

** VIR stock jumped nearly 12% to close at $13.64 on Mon after co said its chronic hepatitis delta (CHD) therapy met primary endpoint in Phase 3 trial

** Co last month inked $1.9 bln licensing deal with Gilead GILD.O for three candidates targeting selected solid tumor-associated antigens

** It intends to use net offering proceeds to fund pre-commercial activities for its CHD program, investments in its T-cell engager (TCE) oncology platform, among other purposes, per the prospectus

** San Francisco, California-based VIR has ~171.3 mln shares outstanding for about $2.1 bln market cap

** Stock, which closed down 7.7% at $12.12 on Thurs, has doubled YTD