Even in the pre-crash era, when real estate prices were surging, nine-figure deals for properties seemed outlandish.

Then beginning in 2015, with ultra-luxury sales on the decline (see: international market volatility and more scrutiny of cash buys) and homes in the seven and eight figures languishing on the market for twice as long as the year before, as well as undergoing price cuts, their existence seemed futile.

Yet, today there are 23 homes on the market priced over $US100 million ($131.04 million).

“It used to be that nothing was in this $US100 million price range, and now we have more than a dozen properties across the country,” says Suzanne Perkins, a Santa Barbara County, California-based real estate agent who is handling several properties above the $US100 million mark.

Just before new year 2015, a condo at New York’s One57 sold for a reported $US100.5 million ($137 million).

Later, a single-family home in Hong Kong’s The Peak neighbourhood sold for $HK1.5 billion ($253 million), allegedly to Alibaba’s Jack Ma.

This year another home in that same neighbourhood sold for $HK830 million.

And let’s not forget the Playboy Mansion, which had a $US200 million price tag and has now been sold, according to numerous reports.

There are at least nine more properties — including massive undeveloped residential lots and private islands — asking $US100 million or more on the market than last year’s 19, according to Christie’s, which scoured public listings and media reports, and probed insider contacts to develop an internal list, which it shared with Bloomberg.

But don’t call it a glut. Call it the price of doing $US100 million dollar business.

According to Dan Conn, CEO of Christie’s International Real Estate, homes in this price range tend to stay on the market for three to five years.

Over the past handful of years, including 2015, he says, the peak number sold was five; three have sold this year. “This feels like a reasonably healthy year,” he says.

The long life of such listings comes in part from the size of the buyer (and seller) pool, or rather, lack of size.

“It’s a really limited universe of buyers and sellers and properties,” says Conn.

Of the world’s richest 200 people, many already have several spectacular, high-priced homes.

“Not every year will a top hedge fund manager buy a $US100 million home. They can stay on the market for a really long time because you don’t have a seller that has to sell, and you don’t have a buyer that has to buy.”

Buyers are more likely looking for a place to park their cash than make an investment that they hope will balloon in worth, so they’ll wait until the right home presents itself.

In other words, the ultra-rich may not actually want a sprawling beachfront mansion in Florida for $US195 million or a $US300 million chateau outside Paris.

And since sellers aren’t usually in a big hurry — fire sales are uncommon in this world, since sellers usually spread their assets around — they aren’t always willing to accommodate negotiations.

“If they get their number they’re happy to go,” says Aaron Kirman, president of Aaroe Estates, whose clientele includes many Middle Eastern royal families. “If they don’t, they love their home, they’re happy to stay.”

“It needs to be irreplaceable and very hard to find,” says Kirman of what lets homes command such high prices.

“It starts with site: the view, the grounds, the privacy, and usually it’s a combo of all of the above. At that price point, it better have it all.”

Architectural or historical significance also drive up the price.

This year’s offerings include a seven-bed, 10-bath duplex on Fifth Avenue in New York; the magnificent “Bubble Palace” once belonging to Pierre Cardin, on the Cote d’Azur in France; and, not to be forgotten, Michael Jackson’s former Neverland Ranch.

Of the 26 on our list, nine were in or near Los Angeles, four were in the New York area, and three were in France. The rest ranged from Panama to Barbados to Switzerland.

Kirman says he has two listings about to sell near the $US100 million mark, and Perkins says a ranch in Montecito is under contract for $US125 million, and she’s expecting a backup offer.

And these are only the ones we know about. Many sellers of $US100 million-plus properties require discretion, and don’t want the world to know they’re unloading an asset.

“We’re aware of other properties that never hit the market publicly,” says Conn of what are known as “pocket listings” or “whisper listings”.

“Some people are shy about letting people know that they’re selling an asset. You have a lot of people at this end of the market that don’t love having publicity around what they’re doing.”

Conn doesn’t know for sure, but he estimates there are a dozen around the world now.

Some of these sellers are so publicity-shy that they wouldn’t allow us to reprint the photographs of their homes, despite the listings being available on the web. (But here you go — there’s this luxury tower in Monaco, allegedly for $US300 million; a castle in Geneva on the market for $US106 million; and the Palais Vénetian in Cannes, which Christie’s has priced at $US105 million.)

Others have proven impossible to confirm. Like the $US500 million property in Los Angeles that topped Christie’s list, which was reported on in May 2015, but the actual listing is nowhere to be found. Of the 23 discovered by Christie’s, 21 have been confirmed, but only the below 14 would let us use images.

The offerings are robust, but chances are slim that there’ll be bidding wars. That Hong Kong home that sold this year for $US107 million was apparently 25 per cent less than analysts predicted. And word has it that the Playboy mansion sold almost 50 per cent of the original ask.

Although, as Conn says, “Fifty percent off $US200 million is still $US100 million.”

Price: $US455 million ($594 million).

Location: Theoule Sur Mer, Provence-Alpes-Cote D’Azur, France.

The Deets: 10 bedroom suites (“decorated by contemporary artists”), 1200 square metres.

Why Is It So Expensive? Designed by the architect Antti LOVAG, Pierre Cardin’s former lair has a 500-seat auditorium and a lounge with panoramic views of the bay of Cannes—and an out-of-this-world style. Think high design versions of Luke Skywalker’s home on Tatooine or a Bond villain’s lair.

Pierre Cardin’s Bubble Palace. Photo: Charles-Henri de La Grandière.

Price: $US195 million ($255 million).

Location: Manalapan, Florida.

The Deets: 33 bedrooms, 34 full and 13 half bathrooms, 7,895 square metres of living space.

Why Is It So Expensive? Land. To be specific, 6.33 hectare if it, in a walled compound, and 1200 feet of beachfront on this barrier island near Palm Beach. It stretches from the ocean to the Intracoastal. The home was originally designed in the 1940s by architect Marion Sims Wyeth, a favourite son of Palm Beach. Also: it is huge.

The Florida mansion has 33 bedrooms. Photo: Premier Estate Properties.

Price: $US159 million ($208 million).

Location: Hillsboro Beach, Florida.

The Deets: 17 beds, 20 full and 11 partial baths, 6,575 square metres.

Why Is It So Expensive? This is not to be confused with Versailles, the 90,000-square-foot home featured in the Queen of Versailles documentary, but it’s still got plenty to boast about (and, hey, it didn’t get stalled like that one). This one is on over 1.6 hectares of beachfront, with the first IMAX home theatre (which can run $US1 million itself), a Go-Kart track, and ice skating rink, and a $US2 million grand staircase.

The Le Palais Royal has a whopping 17 bedrooms. Photo: Sotheby’s International Realty.

Price: $US150 million ($196 million).

Location: Los Angeles.

The Deets: 10 beds, 20 full baths, 3,530 square metres.

Why Is It So Expensive? Yes, location still matters. Carolwood Drive is a prestigious address, and it’s seen a lot of very high-priced sales. Mon Reve was Barbra Streisand’s old estate, where this new home, along with its “Club Mon Reve” — lounge, wine room, theatre complex — now sits. There’s also parking for 50 cars: it’s Hollywood party-ready.

This property is an entertainer’s dream. Photo: Coldwell Banker Residential Brokerage.

Price: $US140 million ($183 million).

Location: East Hampton, New York.

The Deets: 10 beds, 9 baths, 956 square metres.

Why Is It So Expensive? Two words: The Hamptons. This estate has 400 metres of waterfront on Georgica Pond, which you can share with folks like Steven Spielberg and Martha Stewart. The 4.5 hectare property has two residences, designed by architect Peter Marino: a restored Georgian revival and a modern guesthouse. Bigger deal: owners can subdivide into two lots and add additional buildings.

The East Hampton property is on the market for $US 140 million. Photo: Christie’s International Real Estate.

Price: $US135 million ($176 million).

Location: Los Angeles.

The Deets: 7 beds, 10 baths, 1,672 square metres.

Why Is It So Expensive? It’s really about the views, all 360 degrees of them. The 1,672-square metre villa sits atop Los Angeles — high above most neighbours, actually — and the house showcases its spot with a 180-degree dining room. Celebrity pedigrees often carry cachet, though today’s generation of buyers likely hasn’t heard of previous owner Danny Thomas.

The Trousdale Estates compound in Los Angeles. Photo: John Aaroe Group.

Price: $US125 million ($163 million).

Location: Montecito, California.

The Deets: 12 bedrooms, 10 main and three partial baths, 2,739 square metres.

Why Is It So Expensive? Land and location: 95 hilltop hectares. In addition to the gigantic main residence, it has 10 cottages. And according to the broker Perkins, an accepted offer although it hasn’t sold officially yet.

Rancho San Carlos is on the market for $US25 million. Photo: Sotheby’s International Realty.

Price: $US125 million ($163 million).

Location: Saint Peter’s Bay, Barbados.

The Deets: Four residences with five beds, six baths and around 1,207 square metres each.

Why Is It So Expensive? Palazzate is a world unto itself, with four oceanfront homes and a wealth of amenities, from a spa area to staff quarters.

The Palazzate in Barbados has four separate residences. Photo: Caribbean & Co.

Price: $US120 million ($157 million).

Location: New York City.

The Deets: Seven beds, 10 baths, over 1,112 square metres.

Why Is It So Expensive? It’s the “largest existing original apartment on Fifth Avenue.” In other words: before the boom, this 20-room residence was the biggest pad in old New York. It belonged to John Gutfreund, once known as “the King of Wall Street”, who died this year. Rupert Murdoch no longer lives in the building at 834 Fifth Avenue, but you can still be neighbours with his ex-wife Wendi.

This fifth avenue duplex was once home to the ‘King of Wall Street’. Photo: Christies Real Estate.

Price: $US115 million ($150 million).

Location: Los Angeles.

The Deets: Three home sites set on 4.5 hectares.

Why Is It So Expensive? This is Bel Air, baby, and the plot is divisible. Buyers can opt to pay $US45 million for one site, or Domvs, the developer, will build you a 5,200- to 5,670-square-metre house for $US115 million.

The Park Bel Air in Los Angeles. Photo: The Park Bel Air.

Price: $US108 million ($141 million).

Location: Goleta, California.

The Deets: 728 hectares, three kilometres of oceanfront, an seven hectare surface lake.

Why Is It So Expensive? 728 hectares with three kilometres of private ocean frontage, in a part of Santa Barbara County that’s pretty well preserved; you won’t see McMansions sprouting up along this part of the Gaviota Coast. Though it has several residential buildings, it’s being offered as a developable spot for a family compound, vineyard or horse farm.

Las Varas Ranch in California.

Price: $US105 million ($137 million).

Location: Côte d’Azur, France

The Deets: Eight beds, 1,400 square metres.

Why Is It So Expensive? A castle-like property on the Côte D’Azur, overlooking the Mediterranean: views, views, view. It was built in 1900, but feels much older … save for the triangular pool.

The shimmering Mediterranean by Théoule-sur-Mer. Photo: Christie’s International Real Estate.

Price: $US100 million ($131 million).

Location: Los Olivos, California.

The Deets: Six beds, seven full and two partial baths, 1,170 square metres.

Why Is It So Expensive? Michael Jackson’s legacy, a lake and a 510-square-metre movie theatre, on 1,091 hectares northeast of LA. Did we say Michael Jackson?

The former home of Michael Jackson in on the market. Photo: Sotheby’s International Realty.

Price: $US100 million ($131 million).

Location: Great Neck, New York.

The Deets: 13 beds, 35 baths, 5,574 square metre.

Why Is It So Expensive? Three hectares in a gated, waterfront compound, with views of, and easy access to, New York City. Also: a bowling alley and casino. It once belonged to the Soviet billionaire Tamir Sapir.

King’s Point Estate in Great Neck, New York, is like something out of a fairytale. Photo: Coldwell Banker Residential Brokerage.

For more images, see the original story at Bloomberg.