We have one week of 2011 in the books, and once again the market has continued to trend higher virtually without interruption. Just last week I proposed three companies that were at or very near 52-week highs that could be worth letting go. With AutoZone, I couldn't have been more right, but JDS Uniphase continues to taunt my call.

Keep in mind that some companies deserve to be trading at or near new highs. Paychex (Nasdaq: PAYX), for example, continues to outshine its competitors in generating cash flow. But other companies potentially deserve a kick in the pants. Here's a look at three companies that could be worth selling.

Now negotiating sell price
Begin the hate mail now, because it's looking like it's time to let go of priceline.com (Nasdaq: PCLN). It's nothing against William Shatner; on the contrary, none of the other online booking agencies can match priceline's growth rate or its $1 billion in net cash.

My concern stems from the ongoing booking procedure spat between American Airlines (NYSE: AMR) and priceline's competitors, Expedia (Nasdaq: EXPE) and Orbitz. For now, priceline has been mum on whether it's going to side with its peers or American, but this uncertainty has all the potential to spell bad news for the entire industry.

Also troublesome are the slowly rising jet fuel prices, which could put a crimp in consumers' travel plans. Given the above, at 13 times book and seven times sales, I'm willing to live my life sans Priceline.

Network down
Cavium Networks
(Nasdaq: CAVM) looks precariously expensive if you consider that Cisco Systems (Nasdaq: CSCO) is its largest customer right now. Why is that a bad thing? Well, back in November Cisco reported a stinker of a quarter, marked by lower future orders. Current inventories are looking OK, but if this turns into a multi-quarter problem (and I suspect it might), Cavium could be harmed by Cisco's excess inventory.

Statistically speaking, with Cavium trading at nearly 11 times book value and 37 times 2011 earnings projections, I'd have to think there are more attractively valued plays in the networking sector.

Coventry Health Care
(NYSE: CVH) nearly made the list based solely on the stock's steady rise since July, despite an expected double-digit revenue decline in fiscal 2010. What ultimately did Coventry in for me, though, is CEO Allen Wise and his complete disregard for shareholders. He's cashed in on stock option grants, dumping more than half a million option-acquired shares since November to reap net proceeds of nearly $6 million and leaving him with just over 110,000 shares.

Insiders can sell for many reasons, ranging from tax purposes to valuation concerns. After Coventry's meteoric rise on declining revenues, my bet is on the latter. As long as the CEO is selling his stake and revenue remains stymied, even Coventry at a forward earnings multiple of 10 isn't enough to lure me in.

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

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Fool contributor Sean Williams does not own shares in any companies mentioned in this article. He wonders who would win a fight between William Shatner and Chuck Norris. You can follow him on CAPS under the screen name TMFUltraLong. Motley Fool Options has recommended a write covered straddle position on Paychex, which is a Motley Fool Inside Value pick. Coventry Health Care and priceline.com are Motley Fool Stock Advisor choices. The Fool has created a bull call spread position on Cisco Systems. Motley Fool Alpha owns shares of Cisco Systems. Try any of our Foolish newsletter services free for 30 days. The Motley Fool has a disclosure policy.