It's a good week to be a Walton. The trio of siblings behind the Walmart empire have all joined the 12-figure-fortune club, courtesy of a healthy boost to the retailers' share price.

Rob, Jim and Alice are the three children of Sam Walton, who founded the company sitting at the top of the Fortune 500—a ranking it has held for more than a decade.

Founded in 1945, Walmart is the world's largest retailer and is half-owned by two family holding companies.

Alice, aged 74, co-manages one of these two organizations—Walton Enterprises—contributing to her net worth of $101 billion.

As a centi-billionaire, Alice is now the richest woman on the planet, coming in at number 18 on the Bloomberg Billionaires list.

However, she's not the first woman to have ever achieved the centi-billionaire title.

This summer L'Oreal heiress Francoise Bettencourt Meyers was valued at $101 billion but has since seen her fortune tank to $88.2 billion.

Conversely Alice's fortune has grown by $30.8 billion this year alone.

Alice also isn't the only Walton on the Billionaires Index. Her siblings Jim, aged 76, and Rob, aged 79, take the number 16 and 17 spots respectively.

Jim was the first of the trio to crack into the $100 billion club when his fortune leapt to $101 billion in the second week of September. At the time of writing, his fortune was valued at $104 billion.

Rob also joined the centi-billionaire group that week and now has a net worth of $102 billion.

The siblings now join an exclusive club of 18 who are valued at more than $100 billion. The pack is led by Tesla CEO Elon Musk, Amazon founder Jeff Bezos and Meta founder Mark Zuckerberg.

While Alice leads the way as the richest woman on the list, a handful of other heiresses are featured further down. Aside from Bettencourt Meyers, Julia Flesher Koch and her family are valued at $76.8 billion.

Flesher Koch is the widow of David Koch, the former co-owner of multinational conglomerate Koch.

Elsewhere on the list is Melinda French Gates, the ex-wife of Microsoft co-founder Bill Gates, and MacKenzie Scott, who was previously married to Jeff Bezos.

Walmart's growth

Across the American economy retailing has been turbulent, with supply chains disrupted and consumers squeezed.

However Walmart has delivered for shareholders and gained greater market share.

In its Q2 earnings call in August, the group reported revenue of $169.3 billion, up 4.8% compared to the same period the year prior.

"We continue to gain market share, including in general merchandise, and transaction counts and unit volume are up across markets," CEO Douglas McMillon said on the earnings call. "Food continues to be strong and it's encouraging to see improvements in general merchandise. And our US health and wellness business in Walmart and Sam's Club, primarily due to sales of GLP-1 drugs, is contributing to our strong comp sales.