Other than at your wedding, when else will you have the chance to bring everyone you love under one roof, with an open bar, to celebrate and toast and laugh into the early hours of the night?

Most people would say never. But some travel insiders beg to differ.

“Americans nowadays want to get together and celebrate, whether it’s a graduation, or a birthday, or a wedding,” said Frederic Vidal, managing director of Rosewood’s Las Ventanas, a five-star resort in Los Cabos, Mexico. “They’ll take any reason to throw a party.” And by throw a party, he means really throw a party—and buy out a whole resort.

He’s not the only one to notice an uptick in birthday party buyouts among the super wealthy. Jumby Bay, another Rosewood Resort, this one in Antigua, hosted twice the number of birthday buyouts in 2015 than it did in 2014 and is on track to surpass that number in 2016. The Mayflower Grace, in Connecticut, has seen birthday buyouts quadruple in the past two years—and is launching spa packages for fêted guests to encourage that growth to continue. At the Lodge at Glendorn, in Pennsylvania, birthday buyouts have cost as much as $200,000. Most of these properties are reporting such strong birthday business, it’s edging out weddings entirely.

For Jack Ezon, an industry expert and travel specialist at Ovation Vacations, birthday bashes are “the biggest growth market.” Among the parties he’s planned were a $3.5 million spectacle in London that took over Claridge’s and included private events at Buckingham Palace and Spencer House. He’s flown in disk jockeys to private islands in the Caribbean, set up Olympic-style family competitions, chartered yachts, and sent groups on birthday safaris.

Ezon estimates that he books 50 such parties a year—with one-fifth of them costing upward of a million. And though he didn’t plan it, he said the largest one he’d ever heard of was the 60th birthday party of Arcadia Group Chairman Philip Green; it was reportedly a $5 million to $6 million affair at Rosewood Mayakoba (on the Riviera Maya) that included live performances by Stevie Wonder.

At Las Ventanas—a soulful village of whitewashed adobe casitas on the Sea of Cortes—birthday buyouts can range in size. Most often, Vidal sees groups of 10 or 12 taking over a block of suites or villas, typically for a total of $30,000 per day. Only once did he book all 84 suites and villas on property to a single birthday boy—a Texas man who clearly believed in his state’s motto of doing everything bigger. His group, said Vidal, stayed for a three-night weekend, ringing up a bill that likely hovered in the low seven figures.

While Vidal says that “there’s no limit” on what you can spend, he firmly believes these parties are not meant to be ostentatious in any way.

“It’s less about showing off,” he said, “and more about bringing people together.” He says older celebrants will use birthdays as an excuse to reunite the whole family; younger guests swap relatives for friends who are scattered across the country most days of the year.

“They’ll all fly down in one or two planes—and a lot of them are flying private. From California, it’s not that far,” Vidal explained. And once they’re all together, he’ll coordinate group activities, everything from pampering at the spa, to guided wine tastings in a villa, to ATV outings in the desert.

Ira Bloom, chief executive officer of Ani Villas, meanwhile, has built an entire collection of “private resorts” around the idea of destination parties. The first opened in 2011 in Anguilla; two more opened last year in Thailand and Sri Lanka. He plans to open his fourth resort next summer in the Dominican Republic. All are like villas on steroids—gorgeous, exclusive-use compounds built with the aesthetic and ambition of Aman resorts, where clusters of suites have access to pools, a spa, chef services, excursions, and in one case, even a waterslide.

Bloom says that multigenerational reunions make up about half of his bookings and that birthday parties represent about one-sixth of his business. Weddings, on the other hand, are the occasion for one in 10 bookings. The average price of a birthday buyout is $50,000 for five nights for a group of 20, all-inclusive.

“Most often, we see 40th birthday parties for the wives and 50th birthday parties for the husbands,” he told Bloomberg.

For hoteliers, birthday buyouts are covetable business. Not only do they come with massive price tags—they’re also likely to spawn sequels. Several couples that booked 50th birthdays at the Lodge at Glendorn, for instance, have returned 10 years later for 60th birthday parties. Weddings are (in theory) once in a lifetime; milestone birthdays can make for twice-a-decade traditions.

Ultimately, these parties aren’t just about an epic birthday celebration. They’re about a broader desire for quality time and togetherness. That’s why Peter Dauterman, a member of Exclusive Resorts who last year threw a milestone birthday party for his wife at the Peninsula Papagayo, has decided to turn the family reunion into an annual tradition—no occasion needed.

“What surprised us was that the family came together on this trip in a way that they hadn’t since they were kids,” he told Bloomberg in an interview. “It was really more than we expected.”

To contact the author of this story: Nikki Ekstein in New York at nekstein@bloomberg.net.

To contact the editor responsible for this story: Justin Ocean at jocean1@bloomberg.net.

©2016 Bloomberg L.P.

This article was written by Nikki Ekstein from Bloomberg and was legally licensed through the NewsCred publisher network.

Photo Credit: Ani Villas, with properties in Aguillas, Thailand and Sri Lanka, has been built around the destination event concept. Pictured is the Thailand property. Ani Villas