NEW YORK (TheStreet) -- YPF SA (YPF), RenaSola (SOL), and SandRidge Energy (SD) were among the top gainers in the energy space last week, while First Solar (FSLR), FMC Technologies (FTI), and Ecopetrol (EC) topped the losers' list.YPF, an Argentina-based integrated oil and gas company, jumped 17.1% last week, hitting 52-week highs on Thursday. The company obtained a $250 million loan from lender Corporacion Andina de Fomento to finance its investment plan for production, refining and commercialization of petrol and natural gas, Reuters reports. Renesola, a highly rated stock selling at a deep discount, manufactures solar wafers and solar power products. The stock gained around 11.3% last week after Goldman Sachs initiated coverage on the stock with a buy rating and a price target of $11 indicating an upside of 21% over current levels. SandRidge Energy, a natural gas and oil company, continued its gains last week, advancing around 10.8%. Meanwhile, Enerplus Resources Fund ( ERF), McMoRan Exploration ( MMR) and Exterran Holdings ( EXH) gained around 9.5%, 8.9%, and 8.2%, respectively. Chesapeake Energy ( CHK) rose 8.7% following the news that billionaire investor Carl Icahn increased his stake in the company. Holly ( HOC) advanced 8.1% on its announcement that Tulsa refineries will restart operations in a week. CGG Veritas ( CGV), the world's largest seismic surveyor of oilfields, gained 7.9% on the recent uptrend in oil prices, which will likely increase producers' spending. Analysts at Exane BNP Paribas upgraded the stock to outperform from underperform. First Solar and FMC Technologies led the pack of losers, declining around 2.7%, and 2.4%, respectively. Ecopetrol, the largest company in Colombia, declined 1.2% despite it receiving approval from the Brazilian government for participation in Santos Basin. Among other losers, Helix Energy Solutions ( HLX), Oneok Partners ( OKS), and Rosetta Resources ( ROSE) fell 1.1%, 1%, and 1%, respectively.