No matter the market, there will always be a few lagging disappointments holding back a Wall Street rally or several big losers leading a bearish day. The S&P 500 (SNPINDEX:^GSPC) had a strong day as the markets continue their rebound from last week's big losses. But while the index picked up nearly 1%, several stocks took big losses and made investors pull their hair out in frustration. Here are the three worst stocks today that you need to know about -- from education to metals, these stocks put a dent in Wall Street's Wednesday.

Fallout from the "war on coal"
Cliff's Natural Resources (NYSE:CLF) just has not had a very good year so far in 2013. The stock's down 58% year to date and added to the losses today with a 3% drop, bad enough on a good market day to rank among the S&P's biggest losers. Coal miners like Cliff's are on a bind after President Obama gave the go-ahead for federal regulators to limit and cut carbon and greenhouse gas emissions from power plants. Some have dubbed the plan part of a "war on coal," but it's bad news for virtually every coal producer as stocks fell across the industry.

For Cliff's, a stock already under fire throughout the year, it's the kind of blow that makes this stock's upside even harder to see. Cliff's sports a high dividend, but after slashing that by 76% earlier in the year, is that a payout you can really count on? The company also mines iron ore, but considering the mining sector's collapse, there's little hope for an immediate turnaround there, either.

Peabody Energy (NYSE:BTU) is another casualty of the coal mess, with shares down 3.3% today. The plan did offer slim hope for Peabody and other coal producers by looking to improve "clean coal" technology, but with natural gas and oil booming domestically and capturing coal emissions still expensive, the offer seems hardly one that will improve the coal industry's chances in the near future. Peabody's had almost as bad a year as Cliff's in 2013, with the stock down more than 40% year to date. If a ramped-up war on coal is really coming, investors will be hard-pressed to recoup those losses from this stock and its peers.

Still, no stock in the coal sector could match the more than 10% loss of today's biggest loser on the S&P 500, Apollo Group (NASDAQ:APOL). It's not earnings season, but Apollo's earnings crumbled by 40% in the third quarter -- a result that surprisingly beat estimates. Revenue didn't do so well, falling 16% and missing expectations. The real killer? Apollo projected full-year revenue to come in under analyst predictions.

The big picture's far more troubling than one lost quarter for this company. Apollo reported a double-digit percentage decline in student enrollment. Increasing focus and scrutiny on for-profit educators has pressured leading firms in the industry like Apollo, whose University of Phoenix system has become one of the most prominent names in the business. While Apollo's focused on cutting costs in the near future to prop up earnings, it's hard to see enrollment making a real turnaround with the negative PR surrounding the industry. Tread carefully around this stock.

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Fool contributor Dan Carroll has no position in any stocks mentioned, and neither does The Motley Fool. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.