In the 10 years since Barron’s launched its annual best CEOs list, corporate boards have increasingly come under fire. The credit crisis, volatile energy prices, and disruptive technologies turned the decade into something of a CEO killer. Of the 30 CEOs in our original feature, seven have kept their jobs and only two remain on our list: Warren Buffett of Berkshire Hathaway and Michael O’Leary of Ryanair Holdings.
                                                          
Our retention rate has significantly improved in recent years, but the original holdovers convey a lesson beyond just endurance and good health. Buffett and O’Leary have spent their careers challenging the status quo, a too-rare quality that has kept them relevant and successful.
 
In the long run, conventional wisdom shortens CEO careers. As stock buybacks and spinoffs have surged in popularity, Buffett has stayed focused on intrinsic value. In his recent 50th anniversary letter to shareholders, he writes, “Never forget that 2+2 will always equal 4. And when someone tells you how old-fashioned that math is -- zip up your wallet, take a vacation, and come back in a few years to buy stocks at cheap prices.”
                                 
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Berkshire Hathaway has returned an annualized 10% to investors in the past decade and a stunning 22% since Buffett took control of the company in 1965.
 
O’Leary first made our list as a disrupter in the airline industry, promoting a no-frills carrier that flew passengers between European cities. O’Leary’s strategy has managed to fly above Europe’s troubles, while benefiting from the Continent’s growing cohesion. The stock, meanwhile, has returned 300% in the past 10 years, easily outpacing Europe’s legacy carriers, which have been forced into mergers to stay competitive.
 
There’s at least one CEO who would surely have stayed on our list, if he were still alive: Apple’s Steve Jobs made the original list and remained there each year until his death in 2011. This year, for the first time, his successor, Tim Cook, joins the group.
 
Seven other CEOs have been added to the list: Robert Iger of Walt Disney, Joseph Jimenez at Novartis,  Macy’s Terry Lundgren, Sergio Marchionne at Fiat Chrysler Automobiles, Larry Merlo at CVS Health, Under Armour’s Kevin Plank, and Aditya Puri, managing director of India-based HDFC Bank. (Outside the U.S., some chief executives are called by other titles.)
 
Our 30 CEOs hail from all parts of the globe. Twenty of the companies they run are U.S.-based; five are based in Europe, and five are Asian. To see profiles of the 30 leaders in alphabetical order, click here.
 
Eight CEOs have been removed, making way for new faces. They are Amazon.com’s Jeffrey Bezos, Mark Donegan at Precision Castparts, Hugh Grant at Monsanto, Nick Hayek of Swatch Group, CBS head Leslie Moonves, Ford Motor’s Alan Mulally, Norbert Reithofer of BMW, and Lars Rebien Sørensen at Novo Nordisk.
                               
WHILE BARRON’S DOESN’T have a precise formula for constructing the list -- it reflects the collective wisdom of our editors and writers -- we target CEOs with at least five years under their belt. Tim Cook will have four years in August, but he served in an interim capacity while Jobs was sick and helped remake the company’s supply chain as chief operating officer. The Apple Watch -- an entirely new category for the company -- is the surest sign yet that Cook has set his own direction for Apple, which boasts the largest market capitalization in the world, ahead of ExxonMobil.
                               
Swatch arguably has most to lose from Cook’s new business. The Swiss company’s shares have sagged, and investors are unsure about how Hayek, the CEO, will counter the wearable-technology threat.
 
Amazon’s Bezos is gone from our list for the first time since 2008. Bezos remains a visionary leader, but Amazon’s performance in 2014 raised new doubts about the founder’s ability to convert massive sales into profits. Bezos misfired on the Fire phone, taking a massive write-down on unsold inventory.

And his customer-first commitment came into question during a public battle about e-book pricing with publisher Hachette Book Group. Even as tech stocks rallied in 2014, Amazon’s shares fell 22%.
                                  
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Profits, or lack thereof, explain why another corporate visionary, Elon Musk, CEO of Tesla Motors, hasn’t made our list -- yet. Musk is shaking up the automotive world with electric vehicles. But a great CEO needs to generate more than buzz. For now, Tesla is a small company. It has delivered just 57,000 of its flagship cars. Last year it generated $3.2 billion in revenue and lost $294 million. That said, Musk has the maverick quality that propelled Buffett and O’Leary.
 
There will be plenty of room for auto executives to leave their mark in the coming years. From electric vehicles to self-driving cars, the industry has rediscovered its innovative roots. Meanwhile, there’s room for new leaders. Ford Motor’s Mulally retired last year, and BMW’s Reithofer is leaving his post in May; thus, both have come off this year’s list. Fiat Chrysler’s Marchionne is engineering a remarkable turnaround for his transcontinental company after negotiating the merger of the two car makers. He rejoins the list after a two-year hiatus.
 
Some industrial CEOs have had a tough year. Donegan of Precision Castparts is gone because the company’s shares tanked, reflecting sagging demand from the company’s oil and gas customers.
 
In the agricultural world, Monsanto’s Grant has arguably become a victim of his own success. Crop yields have improved so much, partly due to better seeds and herbicides, that excess supplies now weigh on prices.
 
The stock trailed the market sharply in the past year.
 
IGER HAS ENJOYED a decade of success running Disney, and thus merits inclusion on our list. His stewardship of the media and entertainment company has never been stronger -- and at a time when media peers are struggling with splintered audiences and disruptive technologies. Disney’s stock, buoyed by ESPN, theme parks, and the phenomenal success of Frozen, is at an all-time high, up 33% in the past 12 months.
 
Iger’s performance eclipsed that of CBS’ Moonves, another longtime media executive who leaves our list after two years. CBS shares are down 5% in the past year, as the broadcaster struggles with weakened ratings and a soft ad market.
 
Like Iger, Macy’s Lundgren has managed to take a storied brand to new heights. The department-store operator’s profit has more than tripled in the past five years, helped by a growing e-commerce business.
 
Macy’s shelves are full of Under Armour clothes. The athletic-apparel company was founded by Plank in 1996 in his grandmother’s basement. With Plank at the helm, Under Armour profits have grown 30% a year for the past five years, and the stock is up 33% in the past 12 months.
 
CVS Health CEO Merlo made a bold move last year by removing cigarettes and other tobacco products from the stores’ shelves, but he deserves even more praise for broadening his drugstore chain into a leading prescription-benefits manager. Last year, sales rose to a record $139 billion, helped by the growth of in-store health clinics.
 
Jimenez has shown similar skill in managing Novartis, the Swiss health-care giant. During his five-year tenure, Novartis has become Europe’s largest company by market value. Looking ahead, he has positioned the company to take a leading role in the creation of biosimilar drugs. Jimenez takes the spot of Sørensen at Novo Nordisk. Sales growth slowed at the Danish firm, as its diabetes treatments face new competition.
 
The last newcomer is Aditya Puri, who built HDFC Bank almost from the ground up. It is now India’s second-largest private-sector bank, due to the company’s focus on consumer banking, an ideal market given the country’s booming middle class. The stock has gained about 25% annually in the past 20 years, more than double the Indian market.
 
Leadership is a tricky business, and our list will never be perfect. We welcome feedback from readers.