Meanwhile, according to US news outlet Page Six, the mother-of-one has been spending up large.
According to a source, in the months before the pandemic Jenner spent an estimated US$50m-US$70m ($79m-$111m) on a Global Express Jet.
It's believed she had the aircraft fitted out "in the theme of daughter Stormi's birthday".
Her little girl's extravagant birthday celebration was themed "Stormi World" and featured a huge space designed with different themed areas, including a Frozen World.
In April, Kylie also bought a massive US$36.5m ($58m) estate in Holmby Hills, California, plus a US$15m vacant plot of land next to her current home in Hidden Hills, and hired Tom Brady's architect Richard Landry to build a new house.
She also paid US$3.25 million for land at the exclusive Madison Club in Palm Springs, right next to mum Kris Jenner's desert pad, and is building a house there, too.
Considered a generous daughter, she bought her mother a diamond-encrusted Birkin bag and has donated millions to causes including Australia wildfire relief, women's charities and coronavirus relief.
The source said: "Kylie's sisters are concerned about her spending. Yes, she's got a lot of money — but she doesn't seem to realise how easy it is to blow through all of it. She's likely spent over US$130 million in the past year."
Page Six reports reps for the beauty mogul didn't respond to requests for comment.
News of her extravagant spending comes after reports Jenner has been refusing to take phone calls from her mother over Forbes' latest claims.
An insider told The Sun: "Kris – who reportedly gets 10 per cent of Kylie's deals – is in panic mode. Kylie won't answer the phone for Kris and is at a loss over who to trust."
The source added: "Kris is petrified Kylie could sack her or cut her off, so tensions are at an all-time high."
The business magazine claimed the Kylie Cosmetics founder "inflated the size and success of her business for years" and determined she's not a billionaire.
"Forbes has recalculated Kylie's net worth and concluded that she is not a billionaire," reporters Chase Peterson-Withorn and Madeline Berg claimed.
They alleged: "Kylie's business is significantly smaller and less profitable than the family has spent years leading the cosmetics industry and media outlets, including Forbes, to believe."
Forbes then claimed the Kardashians went to "unusual" lengths to prove Kylie's wealth, which included "inviting Forbes into their mansions and CPA's offices, and even creating tax returns that were likely forged".
The magazine had previously labelled the star of Keeping Up With The Kardashians the youngest self-made billionaire in 2019 and she maintained that status in 2020, even after selling 51 per cent of her Kylie Cosmetics company to beauty giant Coty in a deal valued at $1.2 billion.
