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.

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.

Green Dot

One credit services stock that insiders are loading up on here is Green Dot (GDOT - Get Report) , which operates as a technology-centric, pro-consumer bank holding company that provides personal banking for the masses. Insiders are buying this stock into major weakness, since shares have fallen sharply by 30% over the last three months.

Green Dot has a market cap of $778 million and an enterprise value of $157 million. This stock trades at a reasonable valuation, with a trailing price-to-earnings of 16.9 and a forward price-to-earnings of 9.8. Its estimated growth rate for this year is 4.4%, and for next year it's pegged at 9.9%. This is a cash-rich company, since the total cash position on its balance sheet is $771.29 million and its total debt is $151.22 million.

The CEO just bought 206,000 shares, or about $2.98 million worth of stock, at $14.45 per share.

From a technical perspective, GDOT is currently trending below both its 50-day and 200-day moving averages, which is bearish. This stock recently gapped down sharply lower from around $20 a share to under $16 a share with heavy downside volume. Following that move, shares of GDOT went on to print a new 52-week low of $13.87 a share. Since that low, shares of GDOT have started to rebound higher and this stock is now trending within range of triggering a near-term breakout trade.

If you're bullish on GDOT, then I would look for long-biased trades as long as this stock is trending above some key near-term support levels at $14.50 or above its new 52-week low of $13.87 and then once it breaks out above some key near-term overhead resistance levels at $15.63 to around $16 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 680,687 shares. If that breakout begins soon, then GDOT will set up to re-test or possibly take out its next major overhead resistance level at its gap-down-day high of $17.17 a share. Any high-volume move above that level will then give GDOT a chance to re-fill some of its recent gap-down-day zone that started near $20 a share.

Hess

Another stock that insiders are jumping into large here is Hess (HES - Get Report) , which develops, produces, purchases, transports and sells crude oil and natural gas worldwide. Insiders are buying this stock into notable weakness, since shares have trended lower by 27% over the last six months.

Hess has a market cap of $21 billion and an enterprise value of $24 billion. This stock trades at a premium valuation, with trailing price-to-earnings of 9.6 and a forward price-to-earnings of 121. Its estimated growth rate for this year is -155.3%, and for next year it's pegged at 127.3%. This is not a cash-rich company, since the total cash position on its balance sheet is $2.44 billion and its total debt is $5.99 billion. This stock currently sports a dividend yield of 1.4%.

The CEO just bought 57,506 shares, or about $3.99 million worth of stock, at $69.52per share.

From a technical perspective, HES is currently trending just above its 50-day moving average and well below its 200-day moving average, which is neutral trendwise. This stock recently formed a double bottom chart pattern at $63.80 to $63.81 a share. Following that bottom, shares of HES have spiked higher back above its 50-day moving average to its recent high of $74.65 a share. That move has now pushed shares of HES within range of triggering a big breakout trade above some key near-term overhead resistance levels.

If you're in the bull camp on HES, then I would look for long-biased trades as long as this stock is trending above some near-term support at $70 a share or around $67.50 a share and then once it breaks out above some key near-term overhead resistance levels at $74.65 to $75.94 a share and then above more resistance at $77.17 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 3.90 million shares. If that breakout triggers soon, then HES will set up to re-test or possibly take out its next major overhead resistance levels $82.50 to $85 a share, or even its 200-day moving average of $86.77 a share.

Atlas Energy

Another energy stock that insiders are very active in here is Atlas Energy (ATLS , which develops and produces natural gas, crude oil, and natural gas liquids in basins across the U.S. Insiders are buying this stock into major weakness, since shares have dropped by 28% over the last six months.

Atlas Energy has a market cap of $1.5 billion and an enterprise value of $4.7 billion. This stock trades at a reasonable valuation, with a price-to-sales of 0.45 and a price-to-book of 4.54. This is not a cash-rich company, since the total cash position on its balance sheet is $67.47 million and its total debt is $3.27 billion. This stock currently sports a dividend yield of 6.9%.

A beneficial owner just bought 400,000 shares, or about $12.08 million worth of stock, at $30.13 to $30.46 per share. That same beneficial owner also just bought 306,200 shares, or about $9.17 million worth of stock, at $29.55 to $29.86 per share.

From a technical perspective, ATLS is currently trending just above its 50-day moving average and well below its 200-day moving average, which is neutral trendwise. This stock has been uptrending over the last month, with shares moving higher from its low of $24.53 to its recent high of $30.91 a share. During that uptrend, shares of ATLS have been making mostly higher lows and higher highs, which is bullish technical price action. That move has now pushed shares of ATLS within range of triggering a major breakout trade.

If you're bullish on ATLS, then I would look for long-biased trades as long as this stock is trending above its 50-day moving average of $28.84 a share or above $28 a share and then once it breaks out above some near-term overhead resistance levels at $30.91 to $31.47 a share and then above more resistance at $33.04 a share with high volume. Look for a sustained move or close above those levels with volume that registers near or above its three-month average action of 1.13 million shares. If that breakout materializes soon, then ATLS will set up to re-test or possibly take out its next major overhead resistance levels at its 200-day moving average of $37.52 a share to $38.09 or $38.50 a share.

United States Steel

One basic materials stock that insiders are in love with here is United States Steel (X - Get Report) , which provides produces and sells flat-rolled and tubular steel products in North America and Europe. Insiders are buying this stock into large weakness, since shares have tumbled lower by 30% over the last six months.

U.S. Steel has a market cap of $3.5 billion and an enterprise value of $5.7 billion. This stock trades at a reasonable valuation, with a trailing price-to-earnings of 35.4 and a forward price-to-earnings of 8.6. Its estimated growth rate for this year is -55.9%, and for next year it's pegged at 43.7%. This is not a cash-rich company, since the total cash position on its balance sheet is $1.35 billion and its total debt is $3.50 billion.

The CFO just bought 40,083 shares, or about $998,000 worth of stock, at $24.49 to $25.02 per share.

From a technical perspective, X is currently trending below both its 50-day and 200-day moving averages, which is bearish. This stock has been uptrending a bit over the last few weeks, with shares moving higher from its low of $20.09 to its recent high of $25.82 a share. During that uptrend, shares of X have been making mostly higher lows and higher highs, which is bullish technical price action. That move has now pushed shares of X within range of triggering a near-term breakout trade above some key overhead resistance levels.

If you're bullish on X, then I would look for long-biased trades as long as this stock is trending above some key near-term support at $22.86 a share and then once it breaks out above some near-term overhead resistance levels at $25.82 to its 50-day moving average of $25.96 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 8.65 million shares. If that breakout develops soon, then X will set up to re-test or possibly take out its next major overhead resistance levels at $27.65 to $29.19 a share, or even its 200-day moving average of $30.53 to around $33 a share.

Amgen

One final stock with some decent insider buying is Amgen (AMGN - Get Report) , a biotechnology company, which discovers, develops, manufactures and delivers human therapeutics in the areas of oncology, hematology, inflammation, bone health, nephrology, cardiovascular and general medicine worldwide. Insiders are buying this stock into notable strength, since shares have jumped higher by 20% over the last six months.

Amgen has a market cap of $115.9 billion and an enterprise value of $117.7 billion. This stock trades at a reasonable valuation, with a trailing price-to-earnings of 22.7 and a forward price-to-earnings of 14.5. Its estimated growth rate for this year is 7.1%, and for next year it's pegged at 12.8%. This is not a cash-rich company, since the total cash position on its balance sheet is $27.03 billion and its total debt is $30.72 billion. This stock currently sports a dividend yield of 2.1%.

A director just bought 3,000 shares, or about $456,000 worth of stock, at $152.29 per share. From a technical perspective, AMGN is currently trending below its 50-day moving average and above its 200-day moving average, which is neutral trendwise. This stock has been downtrending over the last two months, with shares falling from its high of $172.23 a share to its recent low of $146.64 a share. During that downtrend, shares of AMGN have been making mostly lower highs and lower lows, which is bearish technical price action. That said, shares of AMGN have now started to bounce off that recent low of $146.64 a share and it's now trending within range of triggering a near-term breakout trade.

If you're bullish on AMGN, then I would look for long-biased trades as long as this stock is trending above some near-term support at $146.64 or above $145 a share and then once it breaks out above some key near-term overhead resistance at $155 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 volume of 3.49 million shares. If that breakout gets set off soon, then AMGN will set up to re-test or possibly take out its next major overhead resistance levels at its 50-day moving average of $159 to $160.63 a share, or even $161.90 to $165 a share.

-- 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.