CEOs' perks can include unlimited personal use of the corporate jet. Source: Flickr. 

Skyrocketing CEO compensation is a huge and growing concern for investors -- and no wonder. In 1965, the average CEO of publicly listed companies was paid 20 times more than the average worker. Last year, it was an incredible 303 times more.

When executive compensation gets that extreme, it can take a bite out of company profitability. In fact, "compensation" doesn't really capture the extent of the remuneration of some CEOs. There are stock grants and options, a standard form of compensation at most corporations, but one that boards often fling at top executives with reckless abandon. Perks are also many and lavish, including a company car, chauffeur, and unlimited personal use of the company's corporate aircraft.

Big pay also spells big controversy. Out-sized CEO compensation can make federal and state prosecutors take interest in a company, not to mention stockholder activists. It's also often the case that big pay doesn't equal big results, as is the case with the following examples from two of our Motley Fool contributors.

But what if the company performs well under an exorbitantly paid CEO? The top executive's take can still be so huge it threatens the future stock price. In fact, an analysis of mostly S&P 1500 firms from 1994 through 2011 found a negative correlation between CEO compensation and the company's one- and three-year share-price performance, according to the American Association of Individual Investors.  

Here are three CEOs our contributors believe are among the most rapacious pillagers of shareholder property.

Sean Williams: How bad have things been for the CEO of Sears Holdings (NASDAQ:SHLD), Eddie Lampert? So bad that even a $1 salary seems excessive in my eyes.

OK, so maybe I'm being a bit facetious, but the billionaire investor-turned-CEO of Sears has done a monstrously bad job of running the retailer since taking the helm in January 2013, with shares losing 30% of their value over that time. Despite taking just a $1 annual salary, Lampert was awarded a little over $4.3 million in stock in 2013 for his work as CEO, and he tacked on another $5.7 million in stock last year as a reward for seeing Sears' stock drop another 11%.

You could make the argument that paying Lampert in stock ties his interest in with shareholders (and he has been actively buying shares of stock), but the fact that a billionaire investor is being rewarded at all in stock that could dilute existing investors is beyond preposterous. Not to mention he's getting what are essentially "bonuses" while Sears' stock is falling.

Also, Sears itself is far from healthy. It continues to skate by after reorganizing its crippling debt, revenue has shrunk every year since 2007 -- its trailing 12-month total of $27.4 billion is down nearly 50% from the $53 billion it generated in 2007 -- and the company hasn't generated positive free cash flow on an annual basis since 2010. Put frankly, Lampert hasn't been a very compelling CEO, and his ultra-low Glassdoor approval rating of 20% speaks to that point. It would appear that anything above and beyond $1 per year seems like a bad deal for shareholders.

Cheryl Swanson: John Hammergren, the CEO of healthcare giant McKesson Corporation (NYSE:MCK), saw his salary fall by almost half last fiscal year. Let's not pass the hat for Hammergren just yet, though.

The CEO still took home $25.9 million in salary and stock options, not to mention his reportedly record-setting pension, which was slated to total $159 million, before investors protested. After 78% of shareholders voted against the plan, the company agreed to reduce the pension to $114 million. In my book, that's downright outrageous for a company where front-line employees' pension plans were canceled in 1997.

While McKesson has grown substantially under his tenure, Hammergren has had multiple confrontations with shareholders angry about his compensation package. One key sticking point is the size of Hammergren's so-called "golden parachute" -- those severance packages that ensure no CEO leaves the game without his or her booty wagon loaded, no matter how he or she performs. According to the 2015 proxy statement, McKesson will pay Hammergren $141.7 million in unearned compensation in the event of his termination. When you add that to more than $161 million in severance pay he already has forthcoming, Hammergren's farewell package totals an incredible $300 million.

As one wag said, golden parachutes are lead balloons for investors. While walking away from McKesson would clearly be a win for Hammergren, it's a losing proposition for shareholders. I'm all for reasonable compensation, but this kind of lavish retirement package doesn't lead to an alignment of CEO and shareholder interests. 

Selena Maranjian: It's easy to get outraged at the thought of CEOs who earn many millions of dollars per year. After all, the system is rather rigged, with, as Warren Buffett has noted, compensation committees often featuring "tail-wagging puppy dogs meekly following recommendations by consultants, a breed not known for allegiance to the faceless shareholders who pay their fees."

One CEO who doesn't appear to be earning his generous pay is Richard Adkerson of Freeport-McMoRan Copper & Gold (NYSE:FCX). Earlier this year, the As You Sow organization released a list of the 100 most overpaid CEOs among the 500 companies in the S&P 500 (according to 2013 compensation), and Adkerson was ranked No. 3. His total disclosed compensation was $55.3 million, almost $44 million of which was calculated to be "excess pay," considering the rather poor performance of the company over the previous five years. Freeport's stock is down nearly 60% over the past year and has dropped by an annual average of 21% over the past five years. In its last quarter, revenue plunged 35% year over year.

Freeport has been struggling in recent years, challenged, in part, by falling prices for oil and copper. In 2013, the company bought two other companies, McMoRan Exploration Co. and Plains Exploration, for a whopping $20 billion, once you take assumed debt into account. Shareholders found this an excessive price and sued, with the company settling by paying $137.5 million.

As You Sow is not alone in viewing Adkerson's pay as excessive. A shareholder lawsuit was initiated against the company, protesting a $35 million stock grant awarded to him. The massive award has been rationalized by some as a bargain, considering that should Adkerson leave the company, it will cost the company far more than that, because of excessive severance arrangements. Shareholders in this company are over a barrel.

Cheryl Swanson has no position in any stocks mentioned. Sean Williams has no position in any stocks mentioned. Selena Maranjian has no position in any stocks mentioned. The Motley Fool owns shares of Freeport-McMoRan Copper & Gold,. The Motley Fool recommends McKesson. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.