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 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.

Insiders, however, usually buy their own shares for one reason only: They think the stock is cheap and has tremendous upside.

Recently, a number of companies' corporate insiders have bought stock. These insiders are finding some value in this market, which warrants a closer look at these names.

Arconic

One basic materials player that insiders are active in is Arconic (ARNC - Get Report) , which is engaged in providing materials and engineered products.

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Arconic has a market cap of $13 billion. This stock trades at a reasonable valuation, with a forward price-to-earnings of 20. Its estimated growth rate for this year is 11.2%, and for next year it's pegged at 36.7%. This is not a cash-rich company, since its total cash position is $1.86 billion and its total debt is $8.08 billion.

A beneficial owner just bought 510,000 shares, or $15.53 million worth of stock, at $30.46 per share.

If you're bullish on Arconic, then I would look for long-biased trades as long as this stock is trending above its 20-day at $27.19 a share and then once it breaks out above its 52-week high of $30.69 a share with volume near or above its three-month average of 5.52 million shares. Some possible upside targets are its next major resistance levels at $35 to $37 a share.

NuStar Energy

Another energy player that insiders are jumping into is NuStar Energy (NS - Get Report) , which engages in the transportation of petroleum products and anhydrous ammonia.

NuStar Energy has a market cap of $1.2 billion. This stock trades at a fair valuation, with a forward price-to-earnings of 17. Its estimated growth rate for this year is 31.2%, and for next year it's pegged at 6.7%. This is not a cash-rich company, since its total cash position is $360,000 and its total debt is $30 million.

A director just bought 20,000 shares, or $1 million worth of stock, at $54.03 a share.

If bullish on NuStar Energy, I would look for long-biased trades, if this stock is trending above its 50-day, at 41.43 a share, and then once it breaks out above $54.90, to its 52-week high of $55.64 with volume near or above its three-month average of 112,751 shares. Some possible upside targets are its next major resistance levels at $57 to $60 a share.

Rent-A-Center

One services player insiders are active in is Rent-A-Center (RCII - Get Report) , which leases household durable goods to customers on a rent-to-own basis.

Rent-A-Center has a market cap of $459 million. This stock trades at a cheap valuation, with a forward price-to-earnings of 8.4. Its estimated growth rate for this year is -55.8%, and for next year it's pegged at 200%. This is not a cash-rich company, since its total cash position is $130.30 million and its total debt is $724.92 million.

The CEO just bought 100,000 shares, or about $844,000 worth of stock, at $8.45 per share.

If in the bull camp on Rent-A-Center, I would look for long-biased trades, if this stock is trending over $8 or $7.76 a share, and once it breaks out above resistance at $8.90 to $9.25 a share, with volume near or above its three-month average of 1.82 million shares. If that breakout develops soon, this stock will set up to re-fill its previous gap-down-day zone that started near $10.25 a share.

NuStar GP

One energy player that insiders are in love with is NuStar GP (NSH) . The company engages in the transportation of petroleum products and anhydrous ammonia.

NuStar GP has a market cap of $1.2 billion. This stock trades at a reasonable valuation, with a forward price-to-earnings of 16.9. Its estimated growth rate for this year is 31.2%, and for next year it's pegged at 6.7%. This is not a cash-rich company, since its total cash position is $360,000 and its total debt is $30 million.

A director just bought 40,000 shares, or $1.2 million worth of stock, at $30.02 per share.

If you're bullish on NuStar GP, I would look for long-biased trades, if this stock is trending above key support at $29 or $27 a share, and then once it clears resistance at $31 to its 52-week high of $31.50, with volume near or above its three-month average of 112,751 a shares. Some possible upside targets off that breakout are $35 to $37 a share.

Vista Outdoor

My final stock with some big insider buying is consumer products player Vista Outdoor (VSTO - Get Report) , which is a designer, manufacturer and marketer of consumer products in the outdoor sports and recreation markets.

Vista Outdoor has a market cap of $1.1 billion. This stock trades at a fair valuation, with a forward price-to-earnings of 10. Its estimated growth rate for this year is 19.2%, and for next year its pegged at 1.5%. This is not a cash-rich company, since its total cash position is $40.84 million and its total debt is $1.14 billion.

The CEO bought 20,000 shares, or $416,000 worth of stock, at $20.80 per share.

If bullish on Vista Outdoor, I would look for long-biased trades, if this stock is trending above key support at $20 to $19.72 a share, and then once it clears resistance at $21 to $22.50 a share, with volume near or above its three-month average of 1.50 million shares. Some possible upside targets off that breakout are $23 to its 20-day of $23.93 a share, or $26 a share.

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