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Jacqueline Mars's net worth was $50.3 billion, per Forbes, on its Forbes 400 list of the wealthiest Americans, published 17 September 2026 with wealth priced as of 4 September 2026, ranking her 21st nationally. Six months earlier, the same publisher's "The Richest Women In The World 2026" list, published 10 March 2026 with wealth priced as of 1 March 2026, had her at $49.1 billion, 5th globally among women. Both figures are Forbes, so the roughly $1.2 billion, 2.4% gap between them is one publisher's own number moving over half a year, not two trackers disagreeing.
Forbes' "Richest Women In The World 2026" list placed Jacqueline Mars 5th globally among women at $49.1 billion, having slipped one spot after Chilean businesswoman Iris Fontbona, widow of mining and beverage magnate Andrónico Luksic, rose to 4th at $52.6 billion. Six months later, the Forbes 400, Forbes' annual ranking of the wealthiest Americans, priced her at $50.3 billion, 21st on that list and one of only three women above the $50 billion mark, alongside Alice Walton ($118 billion) and Julia Koch ($84.6 billion). This run found no dated Bloomberg Billionaires Index figure for her more current than November 2023 ($46.6 billion, 23rd globally then), despite several searches, so only the two Forbes figures anchor the before-and-after here. A widely repeated "$40.8 billion, 9 October 2026" figure also surfaced in aggregator search results, but no dated Forbes list or article corroborates it, and the date itself had not yet occurred as this article was verified, so it is not used.
| Date | Publisher | Figure | Context |
|---|---|---|---|
| 1 March 2026 (list pricing date) | Forbes, "The Richest Women In The World 2026" | $49.1 billion | 5th globally among women |
| 4 September 2026 (list pricing date) | Forbes 400 | $50.3 billion | 21st nationally, one of three women above $50bn |
Jacqueline Mars, 86, is a granddaughter of Frank C. Mars, who founded the confectionery company in 1911, and a daughter of Forrest Mars Sr. Forbes describes her stake at roughly one-third of Mars, Incorporated, the same share held by her surviving brother, John Mars. A third sibling, Forrest Mars Jr., died in 2016, and his one-third stake then split among his four children, a multi-heir succession this series has also seen this week at Ciputra Group and Husodo Angkosubroto's Gunung Sewu. Mars is wholly privately held: no shares trade on any exchange, and there is no listed parent company anywhere for NetWort to link to, the same structure this series has used for Sukanto Tanoto's Royal Golden Eagle. She worked inside the company from 1982 to 2001 and sat on its board until 2016, per Wikipedia's sourced biography; she has held no operating role for roughly a quarter century, so today's tracked figure reflects a long-held ownership stake, not an active executive one.
Mars completed its $36 billion acquisition of Kellanova, maker of Pringles, Cheez-It and Pop-Tarts, on 11 December 2025 after receiving final regulatory approval, per Mars's own press release and Food Dive's reporting. The deal was financed largely with debt: Bloomberg reported Mars raised about $26 billion in new bonds and arranged a $29 billion bridge loan, one of the largest debt-funded packaged-food deals on record, and S&P subsequently downgraded its outlook on Mars, citing the added leverage. No source found this run ties the roughly $1.2 billion rise in Mars's own Forbes figure between March and September 2026 to the Kellanova deal specifically, and Forbes' methodology for a private company like Mars typically works from comparable public-company multiples and disclosed financials rather than one transaction, so the acquisition is stated here as dated background, not as an explanation for the number's exact movement.
A wholly private company with three family owners and no public share price is one of the harder fortunes in this series to track, the same shape as Sukanto Tanoto's Royal Golden Eagle. Forbes' own two figures six months apart moved by a modest 2.4%, tight compared with some fortunes this series has covered, but a wide, uncorroborated range from the low $40 billions to the low $50 billions circulates on aggregator sites that rarely name a publisher or a date. That spread is not evidence of volatility the way Masayoshi Son's swings were; it is evidence that estimating a private, multi-generational family conglomerate is inherently harder than pricing a public stock. Treat any figure without both a named publisher and a date as unverifiable.
When a fortune sits entirely inside a private company with no listed shares anywhere, the tracked number is only as good as the publisher's own model, and even the same publisher can move it months apart without one dated event to point to. That is the opposite problem from a fully public, disclosed stock: harder to verify, and easier for a stale or uncorroborated figure to circulate unchecked. For related mechanisms elsewhere in this series, see:
NetWort's market page tracks how publicly traded companies move day to day, the kind of daily pricing a fortune like Mars's, with no listed shares anywhere, never gets.