A realtor who has worked with CEOs and Saudi royals says this is the thing ultra-rich buyers care about most

As one of the top residential real estate agents in the US, Aaron Kirman of John Aaroe Group has worked with his fair share of ultra-high-net-worth individuals.

He counts CEOs, celebrities, and royal families from Saudia Arabia, Qatar, and Kuwait among his clients, and closes between $300 and $400 million in home sales a year.

He also recently reached another big milestone: $3 billion in home sales.

Los Angeles-based Kirman has made his career by understanding and catering to the needs of the wealthy people he works with.

"You really have to connect with your clients. Everyone is looking for something different," he told Business Insider. "The majority of people look at the site, its views, its privacy and scale, or whether it's gated."

Wine rooms, ballrooms, prayer rooms, panic rooms, and decked-out "wellness centers" are among the most-requested amenities.

"In LA, we're not just selling houses," he said. "We're selling the lifestyle, everything from the furniture to the art, to memberships to private clubs."

But there's one thing that Kirman says is an especially big concern among wealthy buyers.

"Really rich people want their privacy. It's a huge issue," Kirman said. "They don't want people to know what they're buying, for multiple reasons."

The practice of using LLCs to hide a buyer's identity is fairly common, and it is legal. In January, the Treasury Department announced that it would begin tracking the masked buyers of high-end properties in New York City and Miami-Dade County. The new initiative will require real-estate companies to reveal the names of people who purchase properties behind shell companies, often in all-cash transactions.

In an investigation conducted by The New York Times last year, it was revealed that nearly half of homes sold for more than $5 million across the country were purchased by shell companies.

For his part, Kirman says that the majority of his sales have happened with the signing of a non-disclosure agreement. Still, he says that it may take some time for the Treasury Department's new policies to make their way out west to Los Angeles.

"It's too soon to tell what will happen. What the government knows and what the public knows may be two different things," he said. "There has been some movement in LA since that policy was announced. Uber-wealthy clients who wanted to buy in New York may now be looking here instead. It has helped my business."

One of Kirman's current listings is the $135 million Danny Thomas Estate in Beverly Hills. The 18,000-square-foot mansion has gold-leaf ceiling and sits on a prime piece of property in the swanky neighborhood of Trousdale Estates.

If sold at the asking price, it would be the most expensive home ever sold in Beverly Hills, beating Minecraft creator Markus Persson's $70 million purchase by a mile.

"There's no science to pricing houses," Kirman said. "We have to go with our knowledge. This house sits on one of very few promontories in Los Angeles. In this neighborhood, you just can't find that."