That threatens to turn the U.S. financial system more fragile in times of market stress, according to Geng Ngarmboonanant, a managing director at JPMorgan and former deputy chief of staff to Treasury Secretary Janet Yellen.

Foreign governments accounted for more than 40% of Treasury holdings in the early 2010s, up from just over 10% in the mid-1990s, he wrote in a New York Times op-ed on Friday. This reliable bloc of investors allowed the U.S. to borrow vast sums at artificially low rates.

“Those easy times are over,” he warned. “Foreign governments now make up less than 15% of the overall Treasury market.”

While they didn’t dump Treasuries and still hold roughly the same amount as 15 years ago, foreign governments didn’t ratchet up their buying in line with the recent surge in U.S. debt, which now tops $38 trillion.

Private investors have stepped in to absorb the massive supply of Treasury bonds, but they are also more likely to demand higher returns, making rates more volatile, Ngarmboonanant pointed out.

The influence of hedge funds, which doubled their presence in the Treasury market in the last four years, raises particular concern among U.S. officials, he added. In fact, the biggest share of U.S. debt that’s held outside the country is now in the Cayman Islands, where many hedge funds are officially based.

Ngarmboonanant attributed “unusual turbulence” during recent shocks in the Treasury market, which has historically been a safe haven during crises, to hedge fund activity. That includes the sudden selloff in the immediate aftermath of President Donald Trump’s shocking “Liberation Day” tariffs.

Relying on AI-fueled productivity gains, stablecoins, Fed rate cuts or inflation to sustain U.S. debt will eventually backfire, he said.

“Financial engineering and false hopes won’t keep America’s lenders happy,” Ngarmboonanant predicted. “Only a credible plan to restrain deficits and control our debt will ultimately do that.”

The ability of bond investors to force lawmakers to change course has earned them the “bond vigilantes” moniker, which was coined by Wall Street veteran Ed Yardeni in the 1980s.

Indeed, upheaval in the bond market after Trump unveiled his global tariffs in April helped convince him to retreat from his most aggressive rates. That prompted economist Nouriel Roubini to say, “the most powerful people in the world are the bond vigilantes.”

But analysts at Piper Sandler recently dismissed the power that bond vigilantes actually have over politicians. 

In an August note, they pointed out that the bond market didn’t prevent federal deficits from exploding and haven’t steered Trump away from continuing to press his overall tariff agenda.

Still, the U.S. debt outlook has become so dire that even longtime Republican Mitt Romney, a former senator and presidential candidate, has called for increasing taxes on the rich as the Social Security Trust Fund races toward insolvency in 2034.

“Today, all of us, including our grandmas, truly are headed for a cliff,” he warned in a recent New York Times op-ed. “Typically, Democrats insist on higher taxes, and Republicans insist on lower spending. But given the magnitude of our national debt as well as the proximity of the cliff, both are necessary.”​

“You cannot teach positive attitudes and engagement and energy,” Sarah Walker tells Fortune. That’s the No. 1 green-flag trait she keeps an eye out for when hiring or looking to promote from within—and she says it outweighs what’s on your resume, especially early in your career. 

The 45-year-old boss spent 25 years climbing the ranks at the Fortune 500 Europe telecommunications giant BT. In that time, Walker went from joining the sales team at the £14.21 billion British ($17.7 billion) legacy brand to leaving as its director of corporate and public sector. Following a micro-retirement, she joined Cisco as managing director before being promoted to lead its U.K. and Ireland arm just two years later. 

Now that she calls the shots, the CEO’s go-to choice for her team is always the upbeat, eager-to-learn worker.

“It’s more about the person first and foremost than it is about skills or experience,” she adds.

Skills become more important with experience—but it always pays to be positive and humble

“I always try and distinguish between the things that can be taught and learnt and the things that are just inherent in somebody,” Walker says, adding that skills become more important as you climb the ladder and enter more specialist roles.

Even then, she says someone with a great attitude and willingness to learn can still bag a role over someone more experienced if they can be developed into the role. 

 “You don’t need to be the finished article to be promoted, but we need to know that you are in a position where within a reasonable timeframe, you’ll have invested the time to upskill and develop—so I say to people, be very focused on who you are first and foremost, because that’s the bit that makes you stand out, and can’t be taught and will be a differentiator,” she adds.

But no matter how junior—or senior—you are, she still thinks a bad attitude will make you stand out for all the wrong reasons.

“I can’t stand arrogance. Be confident, but have a level of humility,” Walker warns. “You can’t rest on your laurels because you’ve done something well in the past, you need to be thinking about what’s the next great thing that you’ll do?”

“Even at my level, you have to be open to the fact that there’s lots more yet to learn and grow and adapt,” she concludes. “I always know that I’m only as good as the last good thing that I’ve done, and I’ll only continue to be good if I continue to do good things.” 

An ’embarrassing’ amount of your success in your 20s depends on your attitude, Jassy echoes

Walker’s not the only CEO to reveal that it’s not a ritzy college degree or being the best networker that will make you stand out at the start of your career—but a positive attitude. Amazon CEO Andy Jassy has said that an “embarrassing amount of how well you do, particularly in your twenties” depends on it.

Even Walker’s predecessor, David Meads previously echoed to Fortune that “EQ is at least as important as IQ.” The now MEA chief at Cisco stressed that he sees “no difference in terms of the capability” from talent with or without a degree while adding that qualifications hold even less weight in external-facing roles.

“You need that EQ to be able to read the room and understand what’s being said by what’s not being said.”

In the end, numerous leaders, including Pret and Kurt Geiger’s CEOs, have stressed that being nice to their boss and coworkers was one of the biggest determining factors in their success.

As Maya Angelou famously said: “People will forget what you said, people will forget what you did, but people will never forget how you made them feel.” And ultimately, the same is true for hiring managers and those with promotion powers.

A version of this story originally published on Fortune.com on January 30, 2025.

During the interview, Galloway highlighted the stark mathematics of modern job searches. “Google puts out a job opening, they get 200 CVs within like eight minutes. They limit it down to the 20 most qualified. Seventy percent of the time, the person they pick is someone who has an internal advocate,” he said.

The advice from Galloway, a marketing professor from the NYU Stern School of Business, aligns with extensive research on hiring patterns. Studies show employee referrals, while representing only 6% to 7% of job applications, account for 37% to 45% of successful hires across various industries, underscoring the importance of making connections. You never know who might be able to help you get your next gig.

Research backs up Galloway’s assertion. Referred candidates are 40% more likely to be hired than those sourced through other means, and people hired through internal referrals tend to perform 25% better and stay 70% longer than employees hired through traditional job boards.

This advice extends to current workplace trends around working remotely versus returning to the office. As you might expect, people who go into the office have a clear advantage as they’re able to be more social with colleagues. According to a 2021 study from the U.K.’s Office of National Statistics, young professionals working remotely are 38% less likely to receive promotions compared to their office-based counterparts.

You can watch the full interview with Scott Galloway and Shane Smith below.