EXCO Resources ( XCO) and TransAtlantic Petroleum ( TAT) erased 4.9% and 4.1%, respectively. LDK Solar ( LDK) retreated 3.4% Noble ( NE) decreased 3% as Global Hunter Securities maintains reduce rating on the stock with a price target of $33 per share. The brokerage's 2011 and 2012 EPS estimates of $1.51 and $3.25 are below consensus estimates of $2.04 and $3.97, respectively. Frontline ( FRO) and TransCanada ( TRP) trimmed 3% and 2.9%, respectively. Yingli Green Energy ( YGE) wiped out 2.7% as Avian Securities maintains a negative outlook on the stock with a price target of $8 per share. Also on the downside were Ecopetrol ( EC) and Transocean ( RIG), closing the week in red with a 2% loss.