The U.S. economy added more jobs than it had in four months in July, provided the spark to send hundreds of companies near new 52-week highs. For skeptics like me, they're opportunities to see whether companies have earned their current valuations.

Keep in mind that some companies deserve their current valuations. Oil and gas exploration giant ExxonMobil (NYSE: XOM) hit a new 52-week high yesterday following another stellar quarterly report in July that highlighted a 49% increase in net income over the year-ago quarter, and a whopping 21% quarterly dividend increase.

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

If you don't build it, the shorts will come
If I didn't know any better, I'd say it was 2006 all over again for the homebuilding sector. The vast majority of homebuilders are seeing double-digit order increases, home prices are beginning to tick higher, and earnings estimates are beginning to rise. As for me, I'm not buying into the optimism one iota given the numerous false bottoms we've witnessed over the years. That's exactly why Louisiana-Pacific (NYSE: LPX), a maker of building products, finds itself on my sell list this week.

Louisiana-Pacific hasn't turned a profit since 2006 despite the Federal Reserve's best efforts to keep rates near 0%. Low mortgage rates do have the potential to spur home buying and construction, but consumers still have limited cash and access to loans with reformed lending standards remaining tight. Even its competitor, Weyerhaeuser (NYSE: WY), cautioned in its recently ended quarter that lumber prices would remain weak and be a drag on its wood products segment in the upcoming quarter. Simply put, there is no easy fix to the housing mess. Until Louisiana-Pacific is steadily profitable, and the housing rebound gets many more months of growth with a reduction in foreclosures under its belt, there's no reason to pay 45 times forward earnings for the company.

A waste of cash?
For this week's episode of a poor use of cash on hand, I'd like to welcome medical device and diagnostic company SurModics (Nasdaq: SRDX) to the pulpit.

SurModics reported its third-quarter results last week and, for the most part, things are slowly moving along in the right direction. In 2011, SurModics sold its pharmaceutical division to Germany's Evonik Industries, and reduced royalty revenue from Johnson & Johnson tied to its Cypher line of stents also stymied revenue. Overall, adjusted revenue rose 17.5%, but figures on a comparable basis will be down for a while considering the loss of these two revenue streams.

What really bugs me about SurModics is the company's announcement of a $55 million modified Dutch auction, whereby it would purchase shares between $17 and $19, only using its cash on hand (which was $108.2 million as of June 30). Theoretically, it could repurchase somewhere between 16.5% and 18.4% of the company's outstanding shares if it exercises the full $55 allotment, which will give an artificial boost to EPS. I personally feel this is just another way of masking the fact that growth in medical devices and diagnostics segments was just 7% in the third quarter, and that the company is valued at a pricey 23 times cash flow and 20 times forward earnings. Why not pay a dividend, look for companies to acquire, or use that cash for further research and development? I don't have the answer to any of these questions, but I very much dislike SurModics' share buyback at new highs.

It's corn, not gold
Unless NASA scientists have discovered how to turn corn into gold, no matter how bad the nationwide drought gets, corn and the Teucrium Corn Fund (NYSE: CORN) that invests in corn futures are bound to come back to Earth.

No one is denying that crop yields will be dismal this year or that inventory levels may worsen further, but the sheer fact that corn prices are tipping the scales at new highs despite no one being able to accurately forecast the weather more than a few days in advance (and even having trouble doing that sometimes) leads me to believe that this is another case of inaccurately trying to predict the weather. It's very possible this drought could continue into next year, but it's much more likely that weather patterns will return to their norms, and so will corn prices. This is a simple case of selling when other investors are being greedy!

Foolish roundup
This week, it's all about profits and greed. Neither Louisiana-Pacific nor SurModics are profitable on a trailing 12 month basis, and their growth prospects leave a lot to be desired based on their forward P/Es. As for the Teucrium Corn Fund, that's just a matter of getting out before you get dragged down with the other greedy investors.

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?

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