Benzinga's Top #PreMarket Losers

National Oilwell Varco

shares fell 9.14% to $74.39 in pre-market trading after the company reported the closing of spinoff of Now. The company also announced the resignation of Miller Jr. as Executive Chairmain and named Clay Williams as replacement. Clovis Oncology

dipped 8.03% to $47.10 in pre-market trading after the company presented encouraging data from Phase 1/2a study evaluating lucitanib in advanced solid tumors at ASCO. Zillow

shares dropped 3.32% to $114.10 in pre-market trading after RBC Capital downgraded the stock from Outperform to Sector Perform. Clean Energy Fuels

dropped 1.44% to $10.92 in pre-market trading after falling 0.89% on Friday.