OKLAHOMA CITY (Reuters) – Nearly 15 years since Enron’s collapse decimated the retirement accounts of its employees, hundreds of thousands of U.S. energy workers remain precariously exposed to big, concentrated bets on company stock in their 401(k) retirement plans.

The slide in oil prices to their lowest levels in over a decade wiped out several billion dollars of retirement wealth in the energy sector in the past year. The losses may prove temporary for companies that successfully navigate the crisis, but tens of thousands of employees of struggling firms may see much of their nest eggs gone for good.

In Oklahoma and Texas, workers are delaying retirement plans, surrendering trucks, cars and land in personal bankruptcy cases, or just praying oil prices will recover.

“I just didn’t see it coming,” said John Thompson, 57, who was laid off in February from Oklahoma City-based SandRidge Energy Inc. SandRidge shares, which peaked above $65 in 2008, are now worth 10 cents apiece. “Because of this, I’m not retiring any time soon.”

SandRidge did not return messages seeking comment.

Almost without exception energy company 401(k) plans offered at least 10 different investment alternatives to company stock, their plans show.

Yet company reports and interviews with more than 20 current and former employees at independent energy firms show many employees have not taken advantage of opportunities to switch out of company shares.

Maureen Nelson, who retired from Chesapeake Energy Corp in 2013, said she lost an estimated $100,000 as she watched the company’s shares plunge in value.

Inertia and a strong faith in company leadership played a role in holding on to company stock, but so did company policies.

Many energy firms continued to match employee contributions with company stock, even as most large U.S. companies stopped the practice after the Enron debacle, according to several corporate benefits consultants.

The energy industry followed the lead of heavyweights such as Chevron Corp and Exxon Mobil Corp, which for years provided matching contributions in company stock in worker 401(k) retirement plans while also funding separate defined benefit pension plans for them.

DOUBLE IMPACT

Smaller companies could not afford to do both, but they typically matched employee contributions in stock. And energy workers often plowed some or most of their own contributions into company stock, benefits consultants said.

“It’s not prudent investing,” said Lou Harvey, chief executive of Boston-based financial research firm Dalbar Inc. “But employees tend to clamor for company stock.”

Typically, workers at larger energy companies would have 20 percent to 60 percent of 401(k) assets in company stock, according to a Reuters analysis of such holdings for more than 400,000 employees.

By contrast, the average U.S. 401(k) plan has about 7 percent of assets in company stock, according to Washington D.C.-based Investment Company Institute.

At Chevron, more than 40,000 participants in its 401(k) plan held $8.9 billion, or 47 percent of investment assets, in company stock at the end of 2014, according to the latest annual report.

Chevron stopped matching in company stock last year for better diversification, spokeswoman Melissa Ritchie said. Exxon stopped new stock contributions after 2006. Its shares still accounted for $12.9 billion of the 401(k) plan’s $22.3 billion in assets in 2014. Exxon declined comment.

When Texas-based Enron filed for bankruptcy in 2001, employees suffered a one-two punch – they lost their jobs and much of their savings because nearly two-thirds of their retirement assets were in Enron stock.

After Enron’s collapse, companies successfully lobbied Congress mostly against proposals to limit company stock ownership in 401(k) plans, fearing billions of dollars of their shares would be offloaded to meet the caps.

“Caps were a bridge too far for companies,” said Sheila Bair, former chair of the Federal Deposit Insurance Corporation and a U.S. Treasury official who worked on President George W. Bush’s 2002 task force on retirement security.

Still, publicly-traded companies have revamped their retirement plans to make them more balanced, even imposing own limits on company stock ownership, said Rob Austin, director of retirement research at Aon Hewitt.

FOLLOW THE LEADER

Diversification has yet to reach much of the energy sector, though. Oil and gas workers had more than $32 billion in company stock in their 401(k) accounts, or about 38 percent of plan assets for the 40 companies in the S&P 500 Energy Sector Index, according to 2014 annual reports filed with the U.S. Department of Labor. Since then, the index has lost 21 percent. Smaller independents have been hit about twice as hard, on average.

With about a third of his 401(k) plan in company stock, retired Chesapeake geologist Keith Rasmussen, 61, looks to sell land he owns in Oklahoma and Idaho to shore up his depleted retirement funds.

Chesapeake, once a shale boom darling, now trades 84 percent below mid-2014 levels, hurt by heavy debt and prolonged slump in natural gas prices. Nearly 8,000 participants in its 401(k) are exposed to the reversal of fortune, holding 35 percent of the plan’s $615 million in assets in company stock at the end of 2014, according to the latest annual report.

Some current and former Chesapeake employees said their decisions to hold onto stock were based partly on their reverence for Aubrey McClendon, its legendary former chief executive, who died in a car crash in early March

“You could be the biggest skeptic in the world, and you listen to him in a room for 30 minutes, and you’re ready to hand him all your money,” said Ginni Kennedy, 58, who retired from her engineering job at Chesapeake in 2013. “I had faith that he’d continue to be able to pull those rabbits out of his hat.”

Chesapeake, which declined to comment, stopped matching in company stock last year.

Many workers are now paying a heavy price for failing to heed warnings about concentration risk.

“Our bankruptcy work has quadrupled over the past six months,” said Roger Ediger, an Enid, Oklahoma lawyer who handles personal bankruptcy cases. “Most of them are energy related.”

A U.S. Supreme Court decision in 2014 underscored the risk of offering company shares in 401(k) plans. Its decision made clear that company stock was not automatically a prudent investment.

The ruling also highlighted the potential conflicts of interest for companies in their role as fiduciary of 401(k) plans.

“It was a wake-up call to companies,” said Bill Ryan, chief fiduciary officer at Evercore Trust, the largest U.S. third-party fiduciary.

At Fort Worth, Texas-based Quicksilver Resources Inc, Evercore Trust took a rare step to block further employee investment in the company’s 401(k) plan in October 2014, as fiduciary for the stock plan. The move preserved some value, but not much, given that by the time the stock fund was liquidated company shares have already fallen to about 50 cents from about $3.50 in 2014. Equity investors lost virtually everything five months later when Quicksilver filed for bankruptcy protection.

Bair, now a college president, said companies with heavy stock concentrations in their 401(k)s should follow peers that have caps in place to protect workers and avoid government mandates.

“If we have another failure like Enron, government regulation may be coming.”

(Reporting By Tim McLaughlin and Luc Cohen; Editing by Tomasz Janowski)