Polski Koncern declined 9.1% during the week. Nexen ( NXY) dipped 8.7% after TD cut Nexen price target on account of a production halt at its Yemen operations due to a labour disruption and curtailed output at its Buzzard assets in the North Sea. The brokerage cut price target by $1 to $26 and maintained a hold rating on the stock. BG Group (BRGYY) declined 8.2% for the week after earnings came below analyst expectations. EPS for the quarter represented a sequential EPS decline of 4% and year-over-year decline of 10%. Net Income for the first quarter stood at $1.014 billion, an average 13% below market consensus of $1.172 billion. Surgutneftegas OAO (SGTPY) dipped 7.9% after expectation of a export tax by Russia on gasoline feedstock, heavy oil product and light oil products. Other underperformers were Surgutneftegas OAO (SGTZY), Yingli Green Energy ( YGE) and LDK Solar ( LDK), erasing 7.5%, 6.9% and 6.9%, respectively. Canadian Natural Resource ( CNQ) accumulated losses of 6.7% on lower than expected first quarter results. The company posted a plunge of 94% in first-quarter profits on a combination of fire at Horizon oil sands and a higher tax rate in the United Kingdom. Among others, OGX Petroleo (OGXPY), Inpex Corporation (IPXHY), Energy Transfer Equity ( ETE) and Tesoro Corporation ( TSO) eroded 6.5%, 6.4%, 6.3% and 5.9% in value, respectively.