Forbes claimed that Kylie and her team "inflated the size and success of her business for years" and declared they believe 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 went on: "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 also added the Kardashians went to "unusual" lengths to prove the wealth of the youngest Jenner including "inviting Forbes into their mansions and CPA's offices, and even creating tax returns that were likely forged."
The magazine had previously labelled Kylie the youngest self-made billionaire in 2019, and 2020. She retained her status even after selling 51 per cent of her Kylie Cosmetics company to Coty in $1.2 billion deal.
Kylie took to Twitter to deny Forbes' claims.
She wrote: "What am I even waking up to. I thought this was a reputable site. All I see are the a number of inaccurate statements and unproven assumptions lol.
"I've never asked for any title or tried to lie my way there EVER. period."
She also denied any forging of her tax returns.
If the reports are true, Kylie could potentially face "serious jail time" if she were "dumb enough" to submit false tax filings a lawyer told The Sun.