When insiders buy their own shares, pay attention. Insiders usually buy their own shares for one reason only: They think the stock is cheap and has huge upside.

One biotechnology player that insiders are active in right now is Bioverativ (BIVV) , which focuses on the research, development and commercialization of therapies for the treatment of hemophilia and other blood disorders.

Bioverativ has a market cap of $6.2 billion. This stock trades at a reasonable valuation, with a forward price-to-earnings ratio of 17.8 times. Its estimated growth rate for this year is 27.8%, and for next year it's pegged at 17%. This is a cash-rich company, since its total cash position is $358.7 million and its total debt is zero.

A director just bought 90,000 shares, or $5.03 million worth of stock, at $55.93 per share.

Bioverativ

If you're bullish on Bioverativ, I would look for long-biased trades as long as this stock is trending above some near-term support at $54.10 or at $51.06, and then once it breaks out above its all-time high of $59.50 with volume near or above its three-month average of 1.32 million shares. Some possible upside targets off that breakout are $65 to $70, or even $75 a share.

Regeneron Pharmaceuticals

Another biotechnology player that insiders are loading up on here is Regeneron Pharmaceuticals (REGN) , which discovers, develops and commercializes medicines for the treatment of serious medical conditions.

Regeneron Pharmaceuticals has a market cap of $50.7 billion. This stock trades at a fair valuation, with a forward price-to-earnings of 31 times. Its estimated growth rate for this year is 11.8%, and for next year it's pegged at 21%. This is a cash-rich company, since its total cash position is $1.31 billion and its total debt is $707.61 million.

A beneficial owner just bought 136,050 shares, or $65.05 million worth of stock, at $466.38 to $484.04 per share.

If you're bullish on Regeneron Pharmaceuticals, I would look for long-biased trades if this stock is trending above its 20-day at $457.86 or above $440, and then once it breaks out above its 52-week high of $489 with volume near or above its three-month average of 957,940 shares. Some possible upside targets off that move are $500 to $520 a share.

Akamai Technologies

One technology player insiders are jumping into here is Akamai Technologies (AKAM) , which is engaged in providing cloud services for delivering, optimizing and securing content and business applications over the internet.

Akamai Technologies has a market cap of $8.4 billion. This stock trades at a fair valuation, with a forward price-to-earnings of 16.8 times. This is a cash-rich company, since its total cash position is $845.1 million and its total debt is $645.72 million.

The CEO just bought 21,196 shares, or $999,000 worth of stock, at $47.17 per share.

If you're in the bull camp on Akamai Technologies, I would look for long-biased trades if this stock is trending above its 52-week low of $46.91 and once it breaks out above resistance levels at $49.06 to $51, with volume near or above its three-month average of 2.50 million shares. Some possible upside targets off that breakout are its 50-day at $54.54 to $57 a share.

Chesapeake Energy

Another energy player that insiders are in love with here is Chesapeake Energy (CHK) , which produces natural gas, oil and natural gas liquids in the U.S.

Chesapeake Energy has a market cap of $4.3 billion. This stock trades at a cheap valuation, with forward price-to-earnings of 4.34 times. Its estimated growth rate for the next quarter is 122.2%, and for next year it's pegged at 31.4%. This is not a cash-rich company, since its total cash position is $249 million and its total debt is $9.52 billion.

A director just bought 75,000 shares, or $374,000 worth of stock, at $5 per share.

If you're bullish on Chesapeake Energy, I would look for long-biased trades if this stock is trending above its recent low of $4.79 or around $4, and then once it breaks out above $5 to $5.22 and over its 20-day at $5.37 to its 50-day at $5.56 with volume near or above its three-month average of 40.37 million shares. Some possible upside targets off that breakout are $5.90 to its 200-day at $6.20 a share.

Avnet

My final stock with some large insider buying is services player Avnet (AVT) , which distributes electronic components, enterprise computer, networking and storage products and software, and embedded subsystems.

Avnet has a market cap of $4.7 billion. This stock trades at a fair valuation, with a forward price-to-earnings 11.8 times. This is not a cash-rich company, since its total cash position is $1.39 billion and its total debt is $1.76 billion.

A director just bought 408,451 shares, or $15.10 million worth of stock, at $36.59 to $37.05 per share.

If you're bullish on Avnet, I would look for long-biased trades if this stock is trending above its recent low of $35.79 and then once it breaks out above resistance levels at $38 to $39 with volume near or above its three-month average of 1.43 million shares. Some possible upside targets off that breakout are its 50-day at $40.22 to its 200-day at $43.13, or even $45 a share.

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

More from Stocks

Inside Carnival's Mind Blowing New Horizon Cruise Ship (Video)

Inside Carnival's Mind Blowing New Horizon Cruise Ship (Video)

Neel Kashkari: The Heart of Our Financial System Is More Radioactive Than Ever

Neel Kashkari: The Heart of Our Financial System Is More Radioactive Than Ever

Finding Stocks Right for You: Cramer's 'Mad Money' Recap (Friday 8/25/18)

Finding Stocks Right for You: Cramer's 'Mad Money' Recap (Friday 8/25/18)

Flashback Friday: Amazon, Chip Stocks, Memorial Day

Flashback Friday: Amazon, Chip Stocks, Memorial Day

Week Ahead: Wall Street Looks to Jobs Report as North Korea Meeting Less Certain

Week Ahead: Wall Street Looks to Jobs Report as North Korea Meeting Less Certain