Following comments by Federal Reserve chairman Ben Bernanke, nearly 56% of stocks within The Motley Fool CAPS Screener database are within 10% of a new 52-week high -- the highest level I can personally ever recall. For skeptics like me, that's an opportunity to see whether companies have earned their current valuations.

Keep in mind that some companies deserve their current valuations. Celgene (CELG), despite its already enormous rally, could have room to run higher according to RBC Capital, which expects big growth out of its drugs not named Revlimid. Based on Celgene's organic growth and expanding disease indications, it's very likely the company could hit its robust growth targets announced earlier this year of a doubling in revenue and a tripling in profits by 2017.

Still, other companies might deserve a kick in the pants. Here's a look at three companies that could be worth selling.

Signal lost
To say that competition is increasing in the satellite television sector would be a gross understatement. Though that hasn't stopped DISH Network (DISH) from hitting a new high despite a cluster of worries that should have scared investors in the opposite direction.

What I believe to be the primary driver behind DISH's strong move higher in recent weeks is ongoing consolidation in the telecommunications sector. AT&T is purchasing Leap Wireless, T-Mobile gobbled up MetroPCS, and SoftBank eventually won over Sprint, but not without a fight. Originally DISH had bid as much as $25.5 billion for Sprint in the hope of expanding its revenue stream solely from pay-per-TV and broadband subscribers to mobile and wireless users. The deal wasn't meant to be, however, as DISH's most recent quarterly report highlighted many of the weaknesses that have me concerned about DISH.

To start with, subscriber growth is slowing dramatically -- just 36,000 additions in the first quarter compared to 104,000 net additions at this time last year. Worse, the cost of getting new subscribers is rising dramatically. Part of the blame can go to tougher competition from its primary rival DIRECTV, but a big chunk can be traced to consumers opting for a cheaper form of entertainment via Netflix or Hulu, utilizing their streaming services to watch movies and shows. Add in the fact that DISH has missed Wall Street's EPS estimates in each of the past four quarters and is slated to grow sales by an average of less than 3% over the next two years despite a forward P/E of 21, and I feel you have all the reasons needed to lose this satellite signal and never look back!

Close this account
Much of the banking sector is on fire in light of rising interest rates that should net them higher net interest margins on their deposits, and because of a rebound in the housing sector that has reinvigorated mortgage origination and refinancing fees. But that doesn't mean every banking stock is an automatic buy.

One that recently crossed my radar as an "avoid" is small-cap bank Seacoast Banking Corp. of Florida (SBCF -0.58%) (henceforth known here as Seacoast to make our lives easier).

I'd be wrong if I didn't point out that Seacoast does have positives working in its favor. The consumer and small-business deposit and loan bank has seen portfolio credit quality improve, has witnessed a nice increase in non-interest-bearing deposits, and produced $119 million in loans during the first quarter. Unfortunately, a lot of the reasoning behind Seacoast's better-than-expected profit is its aggressive cost-cutting measures, which are designed to reduce expenses by as much as $7.4 million in 2013. To put it another way, without cost-cutting, there would be no chance of profitability for Seacoast. It also points to very minimal organic growth, which is not what I'd expect to see from a company up 75% from its 52-week low.

The other factor to consider here is based on valuation and future growth. A big boost over the past quarter came from mortgage fee growth. However, with lending rates surging over the past month, it's quite likely that mortgage fees are going to sour going forward. That's bad news for a bank that's only marginally profitable to begin with. In fact, its forward P/E of 23 is quite pricey considering that it's already valued at 184% of book value and is expected to see net revenue contract. I'd suggest closing this account and not looking back.

Sink or swim
Sometimes the best short-sale opportunities are small, under-the-radar companies. One that I feel fits the bill perfectly is fiberglass boat maker Marine Products (MPX 1.10%).

Like Seacoast, Marine Products has some positives that have helped it to a new 52-week high. The maker of Chaparral and Robalo brand-name boats delivered a 17% increase in sales in the first quarter compared to the previous year, as it sold 12.3% more boats and was able to increase its average selling price by 2.9%. However, there are concerning aspects of this company that I also can't ignore.

For starters, gross margin actually fell during the quarter by 240 basis points despite the increase in sales to 16.1%, because of higher employee labor costs and the sale of more value-oriented boats. If Marine Products can't control its expenses and consumers continue to trade down to lower-margin models, then its margins could contract even further.

Another thing to consider is the health of the U.S. consumer. Although boat buyers tend to be more affluent and are often more immune to economic downturns, the impact of higher taxation on upper-income individuals from Obamacare and the removal of the payroll tax holiday could negatively impact spending from this income class.

Last, but certainly not least, it's a simple call on valuation. There may be decent top-line growth in the mid-to-high single-digits, but there's little growth in EPS because of the ongoing margin contraction. This leaves Marine Products at a lofty forward P/E of 38 after its run higher. Without any real economic visibility and rising labor costs, I'd suggest setting sail.

Foolish roundup
This week's theme is one of my favorites: "Where's the beef?" All three companies have shown flashes of brilliance, but have many unanswered questions moving forward. For DISH it's how to control the rising cost of its falling net subscriptions; for Seacoast, how to boost its bottom line beyond just cost-cutting; and for Marine Products, how to control its expenses if consumers opt for value-priced boats.

I'm so confident in my three calls that I plan to make a CAPScall of underperform on each one. The question is: Would you do the same?