(Updates stocks to reflect prices at close of trading Monday.)

As tough as the day has been on energy stocks, most can count themselves lucky in comparison to the solars this afternoon.

Shares in the sector plummeted, led by Yingli Green Energy ( YGE) and LDK Solar ( LDK), which lost 10.1% and 9.4% by the Monday close.

The likely reasons for the downturn are plentiful. On Thursday afternoon, LDK Solar said it anticipated sales in the second quarter to land between $215 million to $225 million, which was about half as much as last year's second-quarter total. Too bad analysts were predicting sales to come in at a much more robust figure, around $247 million.

Though LDK Solar also said it expected solar wafer shipments to top earlier estimates, investors seemed to pay little attention today.

There's also that bit of news that crude futures continue shedding gains made over the last few months, dragging down a whole host of stocks with it today.

And let's not forget that, as Barron's notes, Barclays Capital analyst Vishal Shah this morning pointed to some troubling signs for the solar sector in the second quarter, lowering price targets and estimates along the way.

Other losing headliners include: Suntech Power ( STP), down 6.9%, or $1.26, to $17.11. SunPower ( SPWRA), down 6.6%, or $1.72, to $24.51. First Solar ( FSLR), down 3%, or $4.60, to $149.60. GT Solar International ( SOLR), down 4.4%, or 24 cents, to $5.17. Trina Solar ( TSL), down 5.5%, or $1.45, to $ 25.01. Claymore/MAC Global Solar Index ( TAN), a solar ETF, was down 5.4%, or 51 cents, to $8.96.
Copyright 2009 TheStreet.com Inc. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.