Stock Quotes in this Article: CLB, GLF, QDEL, T, SAEX

DELAFIELD, Wis. (Stockpickr) -- Corporate insiders sell their own companies' stock for a number of reasons.

They might need the cash for a big personal purchase such as a new house or yacht, or they might need the cash to fund a charity. Sometimes they sell as part of a planned selling program that they have put in place for diversification purposes, which allows them to sell stock in stages instead of selling all at one price.

Other times they sell because they think their stock is overvalued and the risk/reward is no longer attractive. Some even dump their own stock because they have inside knowledge that a competitor is eating their lunch and stealing market share.

But insiders usually buy their own shares for one reason: They think the stock is a bargain and has tremendous upside.

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The key word in that last statement is "think." Just because a corporate insider thinks his or her stock is going to trade higher, that doesn't mean it will play out that way. Insiders can have all the conviction in the world that their stock is a buy, but if the market doesn't agree with them, the stock could end up going nowhere. Also, I say "usually" because sometimes insiders are loaned money by the company to buy their own stock. Those loans are often sweetheart deals and shouldn't be viewed as organic insider buying.

At the end of the day, it's institutional money managers running big mutual funds and hedge funds that drive stock prices, not insiders. That said, many of these savvy stock operators will follow insider buying activity when they agree with the insider that the stock is undervalued and has upside potential. This is why it's so important to always be monitoring insider activity but twice as important to make sure the trend of the stock coincides with the insider buying.

Recently, a number of companies' corporate insiders have bought large amounts of stock. These insiders are finding some value in the market, which warrants a closer look at these stocks. Here's a look five stocks whose insiders have been doing some big buying per SEC filings.

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AT&T

One telecommunications giant that insiders are loading up on here is AT&T (T), which provides telecommunications services to consumers and businesses in the U.S. and internationally. Insiders are buying this stock into modest strength, since shares are up 9.4% so far in 2014.

AT&T has a market cap of $189 billion and an enterprise value of $262 billion. This stock trades at a reasonable valuation, with a trailing price-to-earnings of 10.6 and a forward price-to-earnings of 13.3. Its estimated growth rate for this year is 4.8%, and for next year it's pegged at 3.8%. This is not a cash-rich company, since the total cash position on its balance sheet is $11.30 billion and its total debt is $84.05 billion. This stock currently sports a dividend yield of 5.2%.

A director just bought 100,000 shares, or about $3.56 million worth of stock, at $35.64 per share.

From a technical perspective, T is currently trending above both its 50-day and 200-day moving averages, which is bullish. This stock recently gapped up sharply higher from around $35 to $37.48 to strong upside volume flows. Shares of T are now starting to fill some of that gap to the downside since the stock has started to trend below its gap-down-day low.

If you're bullish on T, then I would wait for this stock to finish re-filling that gap back towards its 50-day moving average of $35.11 a share. Investors will be better served letting shares of T re-fill the gap before jumping in long here. If that gap doesn't get filled, then look to buy on a high-volume move above its 52-week high at $37.48 a share.

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Core Laboratories

Another stock that insiders are jumping into here is Core Laboratories (CLB), which provides reservoir description, production enhancement, and reservoir management services to the oil and gas industry in the Netherlands and internationally. Insiders are buying this stock into notable weakness, since shares are down by 21% so far in 2014.

Core Laboratories has a market cap of 6.6 billion and an enterprise value of $6.9 billion. This stock trades at a premium valuation, with a trailing price-to-earnings of 27.5 and a forward price-to-earnings of 22.6. Its estimated growth rate for this year is 10.2%, and for next year it's pegged at 12.6%. This is not a cash-rich company, since the total cash position on its balance sheet is $29.55 million and its total debt is just $333 million. This stock currently sports a dividend yield of 1.2%.

The CFO just bought 7,000 shares, or about $1.03 million worth of stock, at $146.91 to $148.35 per share.

From a technical perspective, CLB is currently trending below both its 50-day and 200-day moving averages, which is bearish. This stock recently gapped down sharply lower from $167.48 to $146.49 a share. Following that gap, shares of CLB have started to base and move sideways right above that recent low of $146.49 a share.

If you're in the bull camp on CLB, then I would look for long-biased trades as long as this stock is trending above that recent low of $146.49 and then once it breaks out above some near-term overhead resistance at $151.04 a share with high volume. Look for a sustained move or close above that level with volume that hits near or above its three-month average action of 525,864 shares. If that breakout hits soon, then CLB will set up to re-test or possibly take out its next major overhead resistance levels at its 50-day moving average of $160.46 to $165 a share.

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Quidel

One health care player that insiders are in love with here is Quidel (QDEL), which develops, manufactures and markets diagnostic testing solutions for applications in infectious diseases, women's health and gastrointestinal diseases. Insiders are buying this stock into notable weakness, since shares are lower by 22% so far in 2014.

Quidel has a market cap of $824 million and an enterprise value of $803 million. This stock trades at a premium valuation, with a forward price-to-earnings of 95. Its estimated growth rate for this year is -214.3%, and for next year it's pegged at 204.2%. This is a cash-rich company, since the total cash position on its balance sheet is $18.08 million and its total debt is $5.35 million.

The CEO just bought 20,000 shares, or about $482,000 worth of stock, at $24.12 per share.

From a technical perspective, QDEL is currently trending below its 200-day moving average and above its 50-day moving average, which is neutral trendwise. This stock has been uptrending a bit for the last few weeks, with shares moving higher from its low of $20.65 to its recent high of $25.58 a share. During that move, shares of QDEL have been making mostly higher lows and higher highs, which is bullish technical price action. That move has now pushed shares of QDEL within range of triggering a big breakout trade above some key near-term overhead resistance levels.

If you're bullish on QDEL, then I would look for long-biased trades as long as this stock is trending above its 50-day moving average of $22.61 or above more near-term support at $21 and then once it breaks out above its 200-day moving average of $25.50 to more near-term overhead resistance at $25.58 a share with high volume. Look for a sustained move or close above those levels with volume that hits near or above its three-month average volume of 209,732 shares. If that breakout triggers soon, then QDEL will set up to re-test or possibly take out its next major overhead resistance levels at $29 to $30 a share, or even its 52-week high at $32.24 a share.

Read More: 3 Stocks Spiking on Big Volume

Gulfmark Offshore

One energy player that insiders are active in here is Gulfmark Offshore (GLF), which provides offshore marine support and transportation services primarily to companies involved in the offshore exploration and production of oil and natural gas. Insiders are buying this stock into weakness, since shares are off by 17% so far in 2014.

Gulfmark Offshore has a market cap of $1 billion and an enterprise value of $1.55 billion. This stock trades at a cheap valuation, with a trailing price-to-earnings of 12 and a forward price-to-earnings of 8.9. Its estimated growth rate for this year is 35.4%, and for next year it's pegged at 26.7%. This is not a cash-rich company, since the total cash position on its balance sheet is $25.94 million and its total debt is $545.75 million. This stock currently sports a dividend yield of 2.2%.

A vice president just bought 9,000 shares, or about $347,000 worth of stock, at $38.55 per share.

From a technical perspective, GLF is currently trending below both its 50-day and 200-day moving averages, which is bearish. This stock has been downtrending badly for the last two months, with shares moving lower from its high of $46.63 to its recent low of $38.35 a share. During that downtrend, shares of GLF have been consistently making lower highs and lower lows, which is bearish technical price action. That said, shares of GLF have now entered oversold territory, since its current relative strength index reading is 19.76.

If you're bullish on GLF, then I would look for long-biased trades as long as this stock is trending above its recent 52-week low of $38.35 and then once it breaks out above some near-term overhead resistance levels at $39.50 to around $40 a share with high volume. Look for a sustained move or close above those levels with volume that hits near or above its three-month average action of 189,721 shares. If that breakout kicks off soon, then GLF will set up to re-test or possibly take out its next major overhead resistance levels at around $43 to its 50-day moving average of $44.05 a share.

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SAExploration

One final stock with some decent insider buying is SAExploration (SAEX), which provides seismic data acquisition services to the oil and gas industry in North and South America, Southeast Asia, and Africa. Insiders are buying this stock into modest strength, since shares are up by 6% over the last six months.

SAExploration has a market cap of $131 million and an enterprise value of $212 million. This stock trades at a premium valuation, with a price-to-sales of 0.53 and a price-to-book of 11.43. This is not a cash-rich company, since the total cash position on its balance sheet is $13.40 million and its total debt is $94.85 million.

A beneficial owner just bought 56,720 shares, or $468,000 worth of stock, at $8.26 per share. This same beneficial owner also just bought 17,230 shares, or $143,000 worth of stock, at $8.30 per share.

From a technical perspective, SAEX is currently trending above both its 50-day and 200-day moving averages, which is bullish. This stock has been uptrending over the last few weeks, with shares moving higher from its low of $7.95 to its recent high of $8.85 a share. During that uptrend, shares of SAEX have been consistently making higher lows and higher highs, which is bullish technical price action. That move has now pushed shares of SAEX within range of triggering a big breakout trade above some key near-term overhead resistance levels.

If you're bullish on SAEX, then look for long-biased trades as long as this stock is trending above its 50-day moving average of $8.33 and then once it breaks out above some near-term overhead resistance levels at $8.85 to $9 a share with high volume. Look for a sustained move or close above those levels with volume that hits near or above its three-month average action of 15,786 shares. If that breakout materializes soon, then SAEX will set up to re-test or possibly take out its next major overhead resistance levels at $9.81 to $10 a share, or even its 52-week high at $10.35 a share.

To see more stocks with notable insider buying, check out the Stocks With Big Insider Buying portfolio on Stockpickr.

-- Written by Roberto Pedone in Delafield, Wis.


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At the time of publication, author had no positions in stocks mentioned.

Roberto Pedone, based out of Delafield, Wis., is an independent trader who focuses on technical analysis for small- and large-cap stocks, options, futures, commodities and currencies. Roberto studied international business at the Milwaukee School of Engineering, and he spent a year overseas studying business in Lubeck, Germany. His work has appeared on financial outlets including

CNBC.com and Forbes.com. You can follow Pedone on Twitter at www.twitter.com/zerosum24 or @zerosum24.