The fortune of Christy Walton, the world’s wealthiest woman, topped $40 billion Thursday as Wal-Mart Stores Inc. hit an all-time high.

Walton, 65, inherited a piece of the world’s largest retailer in 2005, after the homemade airplane of her husband, John T. Walton, crashed in Wyoming. She’s the world’s ninth- richest person with a net worth of $40.8 billion, according to the Bloomberg Billionaires Index.

“It’s an overwhelming number,” Kristi Hanson, a managing director at Chicago-based CTC myCFO LLC who advises high-net worth individuals and family offices, said in a phone interview. “She’s part of a family dynasty.”

The Walton family, which includes Christy Walton’s siblings-in-law Rob, Jim and Alice Walton, oversee a combined fortune of more than $150 billion. Wal-Mart jumped more than 4 percent today after the Bentonville, Arkansas-based retailer posted third-quarter earnings that beat analysts’ estimates.

Walton’s net worth is also composed of about 25 million shares of First Solar Inc., a Tempe, Arizona-based manufacturer of solar panels. First Solar is down 13 percent for the year.