Gafisa ( GFA) shed 10% past week. Furthermore, steel company Companhia Siderurgica Nacional (CSN) ( SID) dropped 9.3% after the company missed its first-quarter net income estimate. CSN reported net income of $390 million for the quarter as compared to $470 million estimated by four analysts in a Reuters' poll. Energy stocks Petroleo Brasileiro ( PBR) and Ultrapar Participacoes ( UGP) shed 8.0% and 3.7%, respectively, as declining fuel demand pressured oil prices. Basic material stocks Braskem ( BAK) and Vale ( VALE) dipped 7.8% and 7.1%, respectively, last week.