Not even rising oil prices and Egyptian turmoil were enough to keep the Dow and S&P 500 from hitting new multiyear highs this week. For bulls these rallies may seem like dreams come true. For skeptics like me, they're opportunities to see whether companies trading near their 52-week highs really deserve their current valuations.

Keep in mind that some companies deserve their lofty prices. Massey Energy (NYSE: MEE) soared to new heights this week after the company agreed to be purchased for $7.1 billion by Alpha Natural Resources (NYSE: ANR), creating a coal juggernaut. But some companies potentially deserve a kick in the pants. Here's a look at three companies that could be worth selling.

Clinical Data (Nasdaq: CLDA) makes the list after gaining approval from the Food and Drug Administration for its Viibryd depression drug two weeks ago. Although bulls should revel in the gains from an FDA approval, successfully marketing a drug is a completely different ballgame.

The company faces stiff competition from Eli Lilly's (NYSE: LLY) Cymbalta and Forest Labs' (NYSE: FRX) Lexapro, as well as numerous generic antidepressants already on the market. There's no guarantee physicians will opt to prescribe Viibryd before any of the other choices. Clinical Data may choose to put the company up for sale, but as Savient Pharmaceuticals showed recently by failing in its search to find a buyer, that's no guarantee of success either.

In a change of pace, rather than targeting one specific company, a commodity that is looking more speculative by the day is cotton, and the iPath Dow Jones UBS Cottton ETN (NYSE: BAL) might therefore be worth avoiding. Cotton prices have been rising on speculation that India may fall significantly short of production this year. They've also recently been boosted by the political instability in Egypt.

Cotton is currently trading at a 150-year high, and it appears very unlikely that prices can stay this inflated for a long period of time. Eventually, extra suppliers will step in, and that supply should drive these speculative prices lower. This is a commodity exchange-traded note that's priced for perfection.

Liquefied natural gas producer Cheniere Energy (AMEX: LNG) rose to multiyear highs this week on news that Sumitomo had agreed to buy capacity at Cheniere's proposed Louisiana LNG facility. This is good news for bulls, but hardly a slam dunk for the stock. With only one analyst following the company, earnings misses are becoming the norm. Also of concern is the growing short ratio, with 29% of shares currently sold short. A high short ratio isn't an automatic sell, but it is cause for concern. Add in just under $3 billion in debt and a history of losses, and it appears the bears may once again attempt to dig a hole into Cheniere's stock price.

Have an opinion on any of these companies? Let's hear about it in the comments section below!

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Fool contributor Sean Williams does not own shares in any companies mentioned in this article. You can follow him on CAPS under the screen name TMFUltraLong. 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 which never needs to be sold short.