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 Plains

One specialty chemicals player that insiders are in love with here is Green Plains  (GPRE - Get Report) , which produces, markets, and distributes ethanol in the U.S. Insiders are buying this stock into major weakness, since shares have dropped sharply by 36% over the last six months.

Green Plains has a market cap of $806 million and an enterprise value of $1 billion. This stock trades at a cheap valuation, with a trailing price-to-earnings of 6 and a forward price-to-earnings of 5.8. Its estimated growth rate for this year is 209.50%, and for next year it's pegged at -6.2%. This is not a cash-rich company, since the total cash position on its balance sheet is $401.11 million and its total debt is $615.58 million. This stock currently sports a dividend yield of 1.4%.

A beneficial owner just bought 40,000 shares, or about $1 million worth of stock, at $25.16 per share. That same beneficial owner also just bought 160,432 shares, or about $3.98 million worth of stock, at $24.69 per share.

From a technical perspective, GPRE is currently trending below both its 50-day and 200-day moving averages, which is bearish. This stock has been downtrending badly over the last four months, with shares falling from its high of $46.17 to its recent low of $21.19 a share. During that downtrend, shares of GPRE have been consistently making lower highs and lower lows, which is bearish technical price action.

If you're bullish on GPRE, then I would look for long-biased trades as long as this stock is trending above its recent low of $21.19 a share and then once it breaks out above some near-term overhead resistance levels at $24 to $25.94 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 1.43 million shares. If that breakout triggers soon, then GPRE will set up to re-test or possibly take out its next major overhead resistance levels at its 50-day moving average of $28.87 a share to its 200-day moving average of $32.71 a share.

VIVUS

Another biopharmaceutical player that insiders are jumping into here is VIVUS  (VVUS - Get Report) , which, develops and commercializes therapies to address unmet needs in obesity, sleep apnea, diabetes, and sexual health in the U.S. and the European Union. Insiders are buying this into big time weakness, since shares have slid lower by 38% over the last six months.

VIVUS has a market cap of $324 million and an enterprise value of $221 million. This stock trades at a reasonable valuation, with a price-to-sales of 2.23 and a price-to-book of 2.88. Its estimated growth rate for this year is 52.3%, and for next year it's pegged at -34.1%. This is barely a cash-rich company, since the total cash position on its balance sheet is $306.87 million and its total debt is $224.01 million.

A beneficial owner just bought 523,200 shares, or about $1.51 million worth of stock, at $2.09 per share.

From a technical perspective, VVUS is currently trending below both its 50-day and 200-day moving averages, which is bearish. This stock has been downtrending over the last six months, with shares moving lower from over $5 to its new 52-week low of $2.72 a share. During that downtrend, shares of VVUS have been making mostly lower highs and lower lows, which is bearish technical price action. That said, shares of VVUS have now started to bounce higher off that $2.72 low and it's now approaching a near-term breakout trade.

If you're in the bull camp on VVUS, then I would look for long-biased trades as long as this stock is trending above its new 52-week low of $2.72 a share and then once it breaks out above some near-term overhead resistance levels at $3.15 a share to its 50-day moving average of $3.17 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 1.97 million shares. If that breakout develops soon, then VVUS will set up to re-test or possibly take out its next major overhead resistance levels at $3.36 to $3.50 a share, or even $3.70 to around $4 a share.


Ladenburg Thalmann Financial Services

One financial player that insiders are active in here is Ladenburg Thalmann Financial Services  (LTS - Get Report) , which provides brokerage and advisory, investment banking, equity research, institutional sales and trading, asset management, and trust services. Insiders are buying this stock into some strength, since shares have moved higher over the last six months by 11.5%.

Ladenburg Thalmann Financial Services has a market cap of $732 million and an enterprise value of $684 million. This stock trades at a premium valuation, with a trailing price-to-earnings of 96 and a forward price-to-earnings of 197. Its estimated growth rate for this year is 150%. This is a cash-rich company, since the total cash position on its balance sheet is $100.81 million and its total debt is $62.13 million.

A director just bought 100,000, or about $408,000 worth of stock, at $4.09 per share.

From a technical perspective, LTS is currently trending above both its 50-day and 200-day moving averages, which is bullish. This stock has been uptrending over the last month, with shares moving higher from its low of $3.29 to its recent high of $4.23 a share. During that uptrend, shares of LTS have been making mostly higher lows and higher highs, which is bullish technical price action. That move has now pushed shares of LTS within range of triggering a near-term breakout trade.

If you're bullish on LTS, then I would look for long-biased trades as long as this stock is trending above its 200-day moving average of $3.47 a share and then once it breaks out above some key near-term overhead resistance levels at $4.23 to $4.40 a share and then above its 52-week high at $4.50 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 430,722 shares. If that breakout gets started soon, then LTS will set up to enter new 52-week-high territory above $4.50, which is bullish technical price action. Some possible upside targets off that breakout are $5 to $5.50 a share.

Accelerate Diagnostics

One healthcare player that insiders are warming up to here is Accelerate Diagnostics  (AXDX - Get Report) , which focuses on developing and commercializing instrumentation for the rapid identification and antibiotic susceptibility testing of infectious pathogens. Insiders are buying this stock into big weakness, since shares have fallen sharply by 32% over the last three months.

Accelerate Diagnostics has a market cap of $859 million and an enterprise value of $743 million. This stock trades at a premium valuation, with a price-to-book of 11.27. This is a cash-rich company, since the total cash position on its balance sheet is $71.93 million and its total debt is $196,000.

A director just bought 18,000 shares, or about $340,000 worth of stock, at $18.27 per share.

From a technical perspective, AXDX is currently trending below both its 50-day and 200-day moving averages, which is bearish. This stock has recently formed a double bottom chart pattern, since shares have found some buying interest at $17 to $17.50 a share. Following that bottom, shares of AXDX have started to spike higher and it's now quickly approaching a near-term breakout trade above some key overhead resistance levels.

If you're bullish on AXDX, then I would look for long-biased trades as long as this stock is trending above some near-term support levels at $17.54 to $17.50 a share and then once it breaks out above some near-term overhead resistance at $19.66 to $19.80 a share and then above its 200-day at $20.80 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 161,848 shares. If that breakout materializes soon, then AXDX will set up to re-test or possibly take out its next major overhead resistance levels at $22 to $24 a share, or even $25 a share.

Town Sports International

One final stock with some large insider buying is Town Sports International  (CLUB - Get Report) , which owns and operates fitness clubs in the Northeast and Mid-Atlantic regions of the U.S. Insiders are buying this stock into modest weakness, since shares have moved lower over the last six months by 6.1%.

Town Sports International has a market cap of $148 million and an enterprise value of $339 million. This stock trades at a reasonable valuation, with a price-to-book of 0.31. Its estimated growth rate for this year is -169.6%, and for next year it's pegged at -31.2%. This is not a cash-rich company, since the total cash position on its balance sheet is $117.95 million and its total debt is $314.08 million. This stock currently sports a dividend yield of 10.7%.

A director just bought 208,112 shares, or about $1.25 million worth of stock, at $6.01 per share. From a technical perspective, CLUB is currently trending above both its 50-day and 200-day moving averages, which is bullish. This stock has recently formed a major bottoming chart pattern over the last month, with shares finding buying interest at $5.94, $5.80 and $6 a share. Shares of CLUB have now started to bounce modestly higher off those support levels and it's beginning to move within range of triggering a near-term breakout trade above some key overhead resistance levels.

If you're bullish on CLUB, then I would look for long-biased trades as long as this stock is trending above some key near-term support levels at $5.80 or at $5.50 a share and then once it breaks out above some near-term overhead resistance levels at $6.52 to $6.66 a share and then above $6.80 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 113,279 shares. If that breakout begins soon, then CLUB will set up to re-test or possibly take out its next major overhead resistance levels at $7.36 to $8 a share, or even $9 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.

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.