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.

Healthways

One stock that insiders are loading up on here is Healthways (HWAY) , which provides population health management solutions to help people to enhance well-being and health. Insiders are buying this stock into notable weakness, since shares have dropped sharply by 27.7% over the last six months.

Healthways has a market cap of $451 million and an enterprise value of $702 million. This stock trades at a fair valuation, with a forward price-to-earnings of 54.4. Its estimated growth rate for this year is -59.3%, and for next year it's pegged at 109.1%. This is not a cash-rich company, since the total cash position on its balance sheet is $1.76 million and its total debt is $252.45 million.

A director just bought 350,000 shares, or about $4.02 million worth of stock, at $11.31 to $12.10 per share.

From a technical perspective, Healthways is currently trending 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 few weeks, with shares moving higher from its low of $9.93 to its recent high of $12.61 a share. During that uptrend, shares of Healthways have been consistently making higher lows and higher highs, which is bullish technical price action. That move has now pushed this stock within range of triggering a major breakout trade above some near-term overhead resistance levels.

If you're bullish on Healthways, then I would look for long-biased trades as long as this stock is trending above some near-term support at $11 a share and then once it breaks out above some near-term overhead resistance levels at $13 to $13.34 a share and then above more resistance at $14.22 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 374,095 shares. If that breakout triggers soon, then this stock will set up to re-fill some of its previous gap-down-day zone from June that started near $16 a share.

Accelerate Diagnostics

Another stock that insider are active in here is Accelerate Diagnostics (AXDX) - Get Report , which focuses on developing and commercializing solutions for the diagnosis of serious infections. Insiders are buying this stock into notable weakness, since shares have dropped by 22.1% over the last six months.

Accelerate Diagnostics has a market cap of $787 million and an enterprise value of $762 million. This stock trades at a premium valuation, with a price-to-book of 19.96. Its estimated growth rate for next year is -57.1%. This is a cash-rich company, since the total cash position on its balance sheet is $39.03 million and its total debt is just $50,000.

A director just bought 52,837 shares, or about $887,000 worth of stock, at $16.80 per share.

From a technical perspective, Accelerate Diagnostics is currently trending 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 $14.77 to its recent high of $18.85 a share. During that uptrend, shares of Accelerate Diagnostics have been making mostly higher lows and higher highs, which is bullish technical price action. This move has now pushed this stock within range of triggering a big breakout trade above key overhead resistance levels.

If you're in the bull camp on Accelerate Diagnostics, then I would look for long-biased trades as long as this stock is trending above some near-term support at around $16 a share and then once it breaks out above some near-term overhead resistance levels at $18.85 to $19.35 a share and then above more resistance at $19.96 a share with volume that registers near or above its three-month average action of 163,282 shares. If that breakout fires off soon, then this stock will set up to re-test or possibly take out its next major overhead resistance levels at its 200-day moving average of $21.46 to $24 or $25 a share.

Cheniere Energy

An energy stock that insiders are snapping up a large amount of stock in here is Cheniere Energy (LNG) - Get Report , which engages in the liquefied natural gas related business. Insiders are buying this stock into big weakness, since shares have dropped sharply by 40.9% over the last six months.

Cheniere Energy has a market cap of $10.8 billion and an enterprise value of $25.3 billion. This stock trades at a premium valuation, with a price-to-sales of 39.53. Its estimated growth rate for this year is -18%, and for next year it's pegged at 65.6%. This is not a cash-rich company, since the total cash position on its balance sheet is $1.34 billion and its total debt is $15.99 billion.

A beneficial owner just bought 1,000,000 shares, or about $45.45 million worth of stock, at $45.17 to $45.97 per share.

From a technical perspective, Cheniere Energy is currently trending below both its 50-day and 200-day moving averages, which is bearish. This stock recently has been attempting to carve out a double bottom chart pattern, since shares have found some buying interest at $44.25 to $43.96 a share. Following that bottom, shares of Cheniere Energy have now started to trend a bit higher and it's beginning to move within range of triggering a major breakout trade.

If you're bullish on Cheniere Energy, then I would look for long-biased trades as long as this stock is trending above those recent double bottom support levels and then once it breaks out above some near-term overhead resistance levels at its 20-day moving average of $46.97 to its 50-day moving average of $50.16 a share and then above more resistance at $50.33 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 3.84 million shares. If that breakout develops soon, then this stock will set up to re-test or possibly take out its next major overhead resistance levels at $54.95 to $56.50, or
even $60 a share.

Seattle Genetics

One biotechnology stock that insiders are jumping into large here is Seattle Genetics (SGEN) - Get Report , which develops and commercializes antibody-based therapies for the treatment of cancer. Insiders are buying this stock into notable strength, since shares have risen by 16.7% over the last six months.

Seattle Genetics has a market cap of $6.5 billion and an enterprise value of $5.6 billion. This stock trades at a fair valuation, with a price-to-sales of 19.99 and a price-to-book of 9.12. Its estimated growth rate for this year -51.6%, and for next year it's pegged at 58.5%. This is a cash-rich company, since the total cash position on its balance sheet is $736.45 million and its total debt is zero.

A director just bought 934,624 shares, or about $40.14 million worth of stock, at $41.31 to $44 per share.

From a technical perspective, Seattle Genetics is currently trending above both its 50-day and 200-day moving averages, which is bullish. This stock has been uptrending strong over the last month and change, with shares moving higher from its low of $35.94 to its intraday high on Wednesday of $46.74 a share. During that uptrend, shares of Seattle Genetics have been making mostly higher lows and higher highs, which is bullish technical price action. That move has now pushed this stock within range of triggering a near-term breakout trade above some key overhead resistance levels.

If you're bullish on Seattle Genetics, then I would look for long-biased trades as long as this stock is trending above some near-term support at $43 or above its 200-day moving average of $41.08 and then once it breaks out above some near-term overhead resistance levels at $47 to $49.66 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 1.12 million shares. If that breakout gets started soon, then this stock will set up to re-test or possibly take out its next major overhead resistance levels at its 52-week high of $52.33 to $55.99 a share.

Restaurant Brands International

One final stock with some large insider buying is restaurants player Restaurant Brands International (QSR) - Get Report , which owns and operates quick service restaurants under the Burger King and Tim Hortons brand names. Insiders are buying this stock into notable weakness, since shares have dropped by 14.2% over the last three months.

Restaurant Brands International has a market cap of $7.3 billion and an enterprise value of $15 billion. This stock trades at a reasonable valuation, with a forward price-to-earnings of 27.9. Its estimated growth rate for this year is 258.6%, and for next year it's pegged at 17.1%. This is not a cash-rich company, since the total cash position on its balance sheet is $975.50 million and its total debt is $8.79 billion. This stock currently sports a dividend yield of 1.2%.

A director just bought 196,000 shares, or about $6.97 million worth of stock, at $35.29 to $35.76 per share. Another director also just bought 56,600 shares, or about $1.99 million worth of stock, at $34.98 per share. From a technical perspective, Restaurant Brands International is currently trending below both its 50-day and 200-day moving averages, which is bearish. This stock has recently attempted to carve out a double bottom chart pattern, since shares have found some buying interest at $34.19 to $34.82 a share. Following that bottom, shares of Restaurant Brands International have started to bounce higher and it's now quickly moving within range of triggering a near-term breakout trade.

If you're bullish on Restaurants Brands International, then I would look for long-biased trades as long as this stock is trending above those recent double bottom support levels and then once it breaks out above some near-term overhead resistance levels at its 50-day moving average of $37.17 to its 20-day moving average of $37.84 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 1.02 million shares. If that breakout begins soon, then this stock will set up to re-test or possibly take out its next major overhead resistance levels at its 200-day moving average of $39.17 to $41.33 a share.

Disclosure: This article is commentary by an independent contributor. At the time of publication, the author held no positions in the stocks mentioned.