A version of this article first appeared in CNBC’s Inside Wealth newsletter with Robert Frank, a weekly guide to the high-net-worth investor and consumer. Sign up to receive future editions, straight to your inbox.

In 1989, Byron Trott was working at Goldman Sachs in the private wealth management division when he paid a visit to Jack Taylor, founder of Enterprise Rent-A-Car Co.

“Jack was there with his son, Andy, who was running the company,” Trott said. “And they said to me, ‘Sport, I don’t know who told you we have any money, but we are 10 to 1 levered on our business.’ Now, 36 years later, they are one of the model companies of the world, with significant excess cash. And the next generation will not only be maintaining the legacy of Enterprise, Alamo, National Enterprise mobility, but also the legacy of compounding wealth outside the business.”

Part banker, part psychologist and part entrepreneur, Trott has helped many of America’s largest family-led companies grow from cash-starved startups to financial titans. The Walton, Koch, Pritzker, Wrigley, Pulitzer, Heineken and Mars families have all turned to him for advice and guidance. Warren Buffett once called him “the rare investment banker who puts himself in his client’s shoes” and added that “it hurts me to say this — he earns his fee.”

As the ultimate wealth whisperer, Trott has built one of the most valuable networks in banking. And he is at the center of a revolution in private wealth and finance. As the fortunes of business owners like the Taylors have skyrocketed and their family offices have become sophisticated investment firms, wealthy families are buying, selling and building ever-larger companies. The 500 largest family businesses globally generated $8.8 trillion in aggregate revenue and employ 25.1 million people, according to EY.

Trott and his newly expanded firm, BDT & MSD Partners, are quickly becoming the trusted partners to today’s rapidly diversifying families. Formed from the 2023 merger of Trott’s merchant bank with Michael Dell’s family office spin-off, MSD Partners, BDT & MSD Partners helps family-led companies invest in each other, raise capital and diversify their fortunes in other industries.

The firm advised Patagonia founder Yvon Chouinard on his transfer of the company to a special trust and nonprofit. It represented Shari Redstone in the $8 billion merger of Paramount Global with David Ellison’s Skydance Media. And it advised Wyc Grousbeck in his record-shattering sale of the Boston Celtics for $6.1 billion and David Rubenstein’s purchase of the Baltimore Orioles.

“The big advantage we have is we’ve been doing it for so long, for so many of these families and business owners,” Trott told Inside Wealth. “It allows us to really learn through them, their challenges, their objectives, and solve the things that they want to solve. When you add that up over three or four decades, it allows us to be more impactful advisors to the next family that comes to us to get our advice.”

Adds co-CEO Gregg Lemkau: “We always call ourselves long-term investors in a short-term world. The public markets are focused on a quarter, maybe a couple of quarters. Family capital is focused on decades and generations, and that’s how they invest in their businesses.”

With companies staying private for longer rather than going public, the patient capital from wealthy families has become more sought after than ever. BDT & MSD was part of a funding round for Kim Kardashian’s Skims, when it reached a $5 billion valuation. Deals are common between BDT & MSD clients, with one family investing in another’s company or lending their expertise for co-investments.

Along with advice, the firm has about $70 billion under management spread across private capital, private credit and real estate. Fully 95% of its investors are active business owners, family offices or foundations.

With Dell as the chairman of the firm’s advisory council and the largest investor in its funds, BDT & MSD has also quickly become a force in tech. It recently launched a tech fund that raised more than $800 million in just three months and closed in September. Its network of tech clients and partners includes Daniel Ek of Spotify, the Collison brothers of Stripe, Ryan Smith of Qualtrics, and Joe Gebbia of Airbnb.

Mixing young tech founders with the most storied American dynasties has created a new kind of cultural and financial alchemy.

“There is a real magic to having these two worlds come together,” Lemkau said. “The next generation technology founders are so curious about how these businesses have been able to last and be durable and create families around that. And the families are so focused on what’s going on in technology.”

Wealthy families are also turning to the firm for advice on starting and running their family office. After seeing different models for family offices over decades, including the success of Dell’s, Trott and Lemkau said the best family offices share one trait: a clear objective.

“The key is to have real clarity on what the purpose of the family office is,” Lemkau said. “And then it’s about setting up the incentives for the team that’s running that family office to align with those objectives.”

The hottest trend for family offices is direct investing, or buying stakes or companies directly rather than with a private equity fund. It is also filled with perils, since many family offices lack the proper due diligence or professional teams to assess private companies. BDT & MSD, which specializes in direct deals, said families should first learn about direct investing with a top fund, and then gradually progress into direct deals.

“Direct investing is not easy,” Trott said. “The core principles that we tend to live by is you have to have great people, with high integrity, and experience that matters.”

At the heart of all of the largest family businesses and deals, however, are families — usually complicated ones. Advising them on succession, inheritances, raising kids of wealth, passing along values and philanthropy is where BDT & MSD’s decades of experience are paying off.

Trott and Lemkau said the dominant trend with the next generations of wealth holders is the importance of values-based or social-impact-based investing and careers. While families that own large companies used to expect or even require their kids to take over the family businesses, many of today’s next-gen inheritors want to forge their own path.

“In the old days you were raised to take over the family business,” Trott said. “The great thing about this generation, the rising generation, is that they care dearly about impact. They want to impact the world. That’s very consistent across families.”

 The firm also holds regular client gatherings for both children and parents, where families can confide in each other and share experiences, successes and failures. Common questions include how much to leave your kids and when to start teaching them about investing and even whether kids should be able to fly private or be forced to fly commercial.

Trott said the secret to successful family wealth is not about material things – but about values.

“It’s not the house they live in or the jets or the planes or the cars they drive,” he said. “It’s the people in the house and in those cars that are teaching them how to have high integrity, a North Star.”