Predominantly bullish earnings news propelled the Dow briefly to two-year highs above 12,000 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. ConocoPhillips (NYSE: COP) cracked a new high today after reporting better-than-expected fourth-quarter earnings, thanks to higher revenue and firmer oil prices. But other companies potentially deserve a kick in the pants. Here's a look at three companies that could be worth selling.

Wave and sell?
Shares of NXP Semiconductors (Nasdaq: NXPI) have been off to the races the past two months, as investor excitement rises over possible uses for its near-field communications (NFC) wave-and-pay technology. Apple (Nasdaq: AAPL) confirmed this suspicion by announcing it would be using NXP's NFC technology for the next version of the iPhone, potentially leaving credit giants Visa (NYSE: V) and Mastercard (NYSE: MA) out of the loop.

I'm concerned that as soon as this technology becomes viable, competitors will start popping out of the woodwork. NXP may currently have an NFC monopoly, but with $3.7 billion in net debt and lofty expectations, now may be a good time to wave it goodbye.

Pow, to the moon, Alice!
The honeymoon has just begun for shares of satellite broadband provider Hughes Communications (Nasdaq: HUGH), after the company put itself up for sale this week. So why sell now?

Hughes shareholders have wrung every ounce of speculative value out of the stock on news of its sale, and as cliched as this might sound, it's priced for perfection. The company has more than doubled in the past three months. That seems a bit extreme for a company with an estimated 10% long-term growth rate, trading at 163 times trailing-12-month earnings. If traders even get a whiff of something they don't like during this buyout process, the stock could face a sharp sell-off.

Health-care-reform snafu
Since when are falling medical loss ratios anything to be concerned about? When your company's name is HealthSpring (NYSE: HS), and you're heavily reliant on Medicare for your revenue, they're a big worry indeed.

Usually, health-care providers try to maximize profits by spending as little premium as possible on patient care. The measure of this spending is called the medical loss ratio. HealthSpring's MLR for its Medicare Advantage program has steadily fallen to around 78%. The possible dilemma as I see it is that the new health-care reform bill calls for health-care providers to spend between 80% to 85% of premium to ensure that patients get proper care. Whatever earnings momentum HealthSpring has now could disappear as its MLR rises in line with reform standards.

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Fool contributor Sean Williams does not own shares in any companies mentioned in this article. He would love a product that when waved would make all his bills go away. You can follow him on CAPS under the screen name TMFUltraLong. The Fool owns shares of and has written puts on Apple, which is a Motley Fool Stock Advisor pick. 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.