NEW YORK ( TheStreet) -- Energy XXI (Bermuda) ( EXXI), Frontier Oil ( FTO) and Holly ( HOC) emerged top gainers, while Complete Production Services ( CPX), Bristow Group ( BRS) and Petrobras Energia Participaciones ( PZE) headed the losers' list.Energy XXI, analysts' favorite stock during the current earnings season, gained 14.5%, topping energy gainers, after announcing higher-than-expected earnings per share for the quarter ended Dec. 31, 2010. The company reported diluted EPS of 17 cents per share vs. the consensus 12 cents per share, while revenue came in at $174 million vs. the estimated 169.2 million. Frontier Oil swung 13.4% higher after Macquire upgraded the stock to outperform from neutral and Morgan Stanley raised it to overweight from equal weight. Holly advanced 12.2% after Morgan Stanley raised its rating to overweight from equal weight. McMoRan Exploration ( MMR) gained 11.7% after reporting its Davy Jones discovery, among the biggest petroleum finds in the shallow waters of the Gulf of Mexico in decades. Patterson-UTI Energy ( PTEN) rose 11.2% during the week. Citigroup raised the stock to buy from hold, while Duncan Williams upgraded it to strong buy from buy. Tesoro ( TSO) climbed 10.2% after Credit Suisse raised the stock to outperform from neutral, citing upbeat commercial operations and increasing EBITDA in refining. Chesapeake Energy ( CHK) surged 10.0% during the week, despite Lazard capital cutting its rating to sell from hold. The company announced receiving $570 million in cash from CNOOC ( CEO) for a 33% stake in the Niobrara shale project. ReneSola ( SOL) gained 9.9% during the week. Collins Stewart rated Renesola new neutral with a price target $12, implying a 7.2% upside from current prices. Other solar stocks Suntech Power Holdings ( STP), First Solar International ( FSLR), JA Solar Holdings ( JASO), Yingli Green Energy Holdings ( YGE), LDK Solar ( LDK), Trina Solar ( TSL) and GT Solar International ( SOLR) advanced around 7.3%, 7.1%, 6.5%, 4.9%, 4.5%, 4.4% and 2.0%, respectively. Petrohawk Energy ( HK) piled 8.7% even though Lazard Capital cut the stock to sell from hold, and Jefferies revised it to hold from buy. At BMO, the stock was cut to market perform from outperform, whereas SunTrust Robinson raised the stock to buy from neutral. UBS has raised Petrohawk's price target to $26 from $24. Cameron International ( CAM) soared 8.6% last week. Citigroup raised its price target to $58 from $54, while maintaining its hold rating. Jefferies raised its target to $67 from $57, reiterating a buy rating, as analysts believe that the stock's upbeat momentum will continue following the company's fourth-quarter results. However, Guggenheim has downgraded the stock to neutral from buy.