Who says that old people are wiser? Just because you’ve lived longer than someone else doesn’t mean you know more than they do.

This isn’t to say that younger people hold an equal amount of prestigious jobs compared to their older counterparts. Most of the brilliant academics, scientists, doctors, and leaders are relatively “seasoned” in life. The same is true for CEOs. It’s highly unusual to see a CEO of a major company less than 40 years old.

Recently though, some high-profile companies have started to hire relatively young CEOs, or those under the age of 40. We felt it’s worth examining just how well these young CEOs are doing. We found most of the young CEOs of big companies have been successful, with one exception:

Andrew Mason

Former CEO, Groupon (GRPN)

Andrew Mason is the founder and former CEO of the legendary smart phone application Groupon. Only 28 when he crated Groupon, Mason soared into the spotlight, and then fell out of it just as qucikly. In 2012, Herb Greenberg of CNBC named Mason worst CEO of the year. Mason was also regularly criticized for his “goofy” behavior and when a terrible Q4 earnings report came out in early 2013, Mason was dismissed from his post as CEO.

Since Groupon’s IPO in June 2011, the stock price has depreciated nearly 80% in value from $25 to only $5.

Aside from Mason, the rest have done pretty well for themselves.

Mark Zuckerberg

CEO, Facebook (FB)

Perhaps the most famous and well-known young CEO, Mark Zuckerberg famously founded Facebook during his time at Harvard. After a highly contentious lawsuit with former partner Eduardo Saverin as well as Cameron and Tyler Winklevoss, Zuckerberg grew Facebook into the multi-billion dollar giant it is today.

Becoming the youngest billionaire ever, Mark Zuckerberg presided over the rise of the largest social network in history, and Facebook continues to grow even more.

In the past two years, Facebook’s stock has appreciated almost 400% in value from $20 to $75.

Marissa Mayer

CEO, Yahoo! (YHOO)

Marissa Mayer was among the first to sign with Google in 1999. She worked there for 13 years and was actually the first female engineer that Google hired. In 2012, Yahoo hired her away with a lucrative $117 million contract over 5 years.

Since her arrival at Yahoo in July 2012, Mayer has completely changed the culture of Yahoo’s workplace. She required all employees who worked from home to come into the office, introduced an evaluation system for managers to assess how well their workers are performing, and oversaw the acquisition of Tumblr.

Since Mayer has assumed her role of CEO, Yahoo overtook Google (GOOG) to become the most visited web company on the planet, and shares of Yahoo have appreciated 230% in value from $15 to $35. She is still only 39 years old.

Daniel Schwartz

CEO, Burger King (BKW)

At only 32 years old, Daniel Schwartz was the youngest man ever to be named CEO of Burger King. A graduate of Cornell University, Schwartz spent nearly ten years on Wall Street before coming over to BK last summer.

Burger King, which was purchased for $4 billion in 2010 through a leveraged buyout by 3G, just went public again in June 2012. Since it went public two years ago, market capitalization has increased from $4.6 billion to $9 billion. In his short time there, Mr. Schwartz has already made a notable impression.

In one year, Burger King’s shares have appreciated more than 20% in value.

Ed Rosenfeld

CEO, Steve Madden (SHOO)

A former investment banker and VP for the Peter J. Solomon Company, Ed Rosenfeld assumed the role of CEO of Steve Madden on August 8, 2008. Since that time, the company has thrived through various acquisitions, strategic partnerships, and “some nurturing of orphaned designers.”

Although Mr. Rosenfeld has been largely successful by most measures, much of this success can be attributed to the resurgence of the company’s founder: Mr. Steve Madden. Since his stint in prison for stock fraud almost a decade ago, Mr. Madden has taken a far more vested interest in his company. The combination of Mr. Madden and Mr. Rosenfeld seems to be working very nicely for the company.

Since February of 2008, shares of Steve Madden have appreciated nearly 700% from $5 to $35.

Justin Hutchens

CEO, National Health Investors (NHI)

Originally joining NHI as president and COO in February 2009, Mr. Hutchens was appointed to CEO just two years later in March 2011. Prior to NHI, Mr. Hutchens had an extensive background in senior care operations. He worked in several nursing facilities and also held high level management positions at Emeritus Senior Living ($ESC).

Since Mr. Hutchens assumed the position of CEO, shares of NHI have appreciated roughly 30% in value.