NEW YORK ( TheStreet) -- Atlas Pipeline Partners ( APL), Sunoco ( SUN) and Chesapeake Midstream Partners ( CHKM) were top gainers last week, while LDK Solar ( LDK), Suntech Power Holdings ( STP) and Cheniere Energy Partners ( CQP) lost considerable ground, topping the losers' list.

Atlas Pipeline Partners ( APL), owner and operator of natural gas pipeline gathering systems in U.S., gained 3.4%. Morgan Stanley raised its price target on Atlas to $38 from $35 and maintained its overweight rating on the stock. The bank sees Atlas's 2011 earnings at $1.68 per share and 2012 earnings at $2.23 per share.

Sunoco ( SUN) surged 2.2% last week after reporting better-than-expected quarterly numbers. Net income increased to $87 million or $0.72 per diluted share for 2010 fourth quarter, compared to $26 million or $0.22 per diluted share during the same quarter in 2009. The yearly financial numbers also staged a comeback. Sunoco reported net income of $234 million for 2010 versus a net loss of $329 million for full-year 2009.

Chesapeake Midstream Partners ( CHKM) and Quicksilver Resources ( KWK) advanced 2.1% and 1.95%, respectively.

Sinpoec ( SNP) gained 1.6%. The company said it has met or even surpassed the operational targets for the first quarter of 2011. During the week, the company asked its refining plants to boost gasoline output, says parent China Petrochemical.

Other movers TransCanada ( TRP), Weatherford International ( WFT), OGE Energy ( OGE) and PetroChina ( PTR) were flat, up 0.96%, 0.7%, 0.14% and 0.11%, respectively.

LDK Solar ( LDK) was the top loser, plummeting 15.3%. Lazard Capital downgraded LDK Solar to hold from buy. Lazard Capital expects industry pricing to decline faster than expected, given the expected policy changes in Italy and Germany.

Suntech Power Holdings ( STP) shed 14.7% last week. HSBC downgraded Suntech Power to underweight from neutral with a target price of $6.6 per share.

Cheniere Energy Partners ( CQP) continued its losing streak for the second straight week, plunging 13.2%. Other prominent losers were SunPower ( SPWRA), GT Solar International ( SOLR), Oasis Petroleum ( OAS), Trina Solar ( TSL) and JA Solar Holdings ( JASO), down 13.1%, 11.3%, 10.9%, 10.6% and 9.8%, respectively.

Canadian Natural Resources ( CNQ) erased 9.1% after reporting disappointing fourth quarter results.

Suncor Energy ( SU) declined 8.6%. Beginning March 20, 2011, Suncor Sarnia plans partial shutdown of certain units for about six weeks.

Whiting Petroleum ( WLL) dipped 7.6%. Morgan Keegan downgraded the stock to market perform from outperform and recommends taking profits in light of the current spike in oil prices. The firm recommends a price target of $73.

Among others, Swift Energy ( SFY), Cenovus Energy ( CVE), BreitBurn Energy Partners ( BBEP) and Berry Petroleum ( BRY) shed 9.8%, 9.2%, 8.7% and 8.7%, respectively.