Autry Stephens sold his company for $26 billion but died before the deal was done. Here's how a Texas farm boy became an oil tycoon.

• Autry Stephens sold his oil company for $26 billion but died before the deal was completed.
• The Texan farm boy became an oil tycoon by betting big, minimizing costs, and working tirelessly.
• Here's a closer look at Stephens' life and the monster deal he struck months before his death.

Autry Stephens spent 45 years building one of the nation's largest private oil producers and finally agreed to sell it for $26 billion this year — but died before the deal closed .

The Texas farm boy became an oil tycoon by taking big risks, pinching pennies, hustling hard, and finding ways to survive when others failed. Here's the story of his life and his last big deal.

Drilling down

Stephens was born in 1938, raised on a fruit-and-peanut farm in the Texas town of DeLeon, and studied petroleum engineering at the University of Texas at Austin's engineering school, according to a profile on its website.

His first job after graduating was at Humble Oil, an ExxonMobil predecessor. He promptly took two years out to join the US Army Corps of Engineers as a lieutenant and platoon leader in charge of installing pipelines before rejoining Humble for five years.

His next gig was as an appraisal engineer for a bank in Midland, Texas. Next, he struck out on his own as an independent consulting engineer.

Stephens was in his forties by the time he drilled his first well in 1979. He plowed his life savings into the prospect, which "wasn't very smart," he told The Wall Street Journal in February.

Over the next 45 years the wildcatter established Big Dog Drilling Company, which had a single rig at first, and then Endeavor Energy Resources. He built his business into one of the biggest oil exploration and production companies in the Permian Basin of West Texas and New Mexico.

Endeavor now owns 410,000 net acres across multiple basins, boasts thousands of wells, and produces more than 420,000 gross operated barrels of oil equivalent per day, according to its website.

Striking oil

Stephens competed with the oil majors as an underdog, purchasing wells they deemed too costly to bring online. He drove down costs by drilling one well at a time, and buying or setting up his own fracking, trucking, construction, and oil services companies.

When rivals faltered during industry downturns, Stephens bought cheap mineral rights and acquired businesses for his stable. He stayed afloat when crude prices plunged in 2008 and 2014 by shutting down his rigs, flogging assets, and securing new lenders, per the Journal. He also issued long-term bonds and stabilized the selling prices for his oil using futures contracts, per Bloomberg.

Endeavor has been riding high on the US shale wave since 2016, when it shifted its focus to fracking and horizontal drilling. Stephens told the Journal that he'd been fending off buyout offers from ExxonMobil and Shell for years.

He finally accepted a $26 billion deal for Endeavor from Diamondback Energy in February. One big reason was that he'd been diagnosed with cancer, and the disease was taking a physical toll on him, he told the Journal.

Work hard, spend little

Stephens was renowned for his zealous work ethic . The Journal reported that he often went to Endeavor's offices at weekends, and marched up and down the staircases for exercise.

He also took a leaf out of Warren Buffett's frugal billionaire playbook. He flew cheaply with Southwest Airlines , drove a beaten-up Toyota Land Cruiser, and didn't take any money out of Endeavor for many years, sources told the Journal.

Stephens also kept a low profile. One of his few moments in the spotlight was on a truTV documentary called "Black Gold," which followed workers on one of his rigs as they scrambled to complete four wells in 50 days.

Missing out

Diamondback is set to buy Endeavor for $8 billion in cash and 117 million shares.

The merger promised to quadruple Stephens' net worth to more than $23 billion on paper, vaulting him to 85th place on the Bloomberg Billionaires Index and making him America's wealthiest oilman.

Stephens has now been removed from the rich list following his death on August 16 at the age of 86. He was previously listed as gaining some $17 billion this year — more than Elon Musk (up $4.2 billion), Microsoft's Steve Ballmer (up $11.8 billion), and Asia's richest person, Mukesh Ambani (up $16 billion).

The wildcatter died shortly before the deal's expected fourth-quarter close. But given Stephens' disinterest in living large, it's unlikely he felt bitter about missing out. His family is set to receive the payment instead.

Stephens told the Journal in February he had "mixed emotions" about selling the company he'd built over more than four decades. He viewed his workforce as a "kind of a little family" and would miss them.