Forbes magazine has alleged Saudi tycoon Prince Alwaleed bin Talal "systematically exaggerates" his wealth after the billionaire accused the magazine of understating the size of his fortune.
Alwaleed announced he was severing his ties with Forbes after it reported in its annual billionaires' list that he was only worth $US20 billion ($A19.74 billion), $US9.6 billion less than the prince claims.
In its 2013 list published on Monday, Forbes ranked Alwaleed the world's 26th top billionaire, naming him the richest man in the Arab world.
But immediately after the list came out, the prince's office and his Kingdom Holding investment group announced they "have ended their long-standing relationship with the Forbes Billionaires List".
In a statement, Kingdom said its officials would no longer work with Forbes' valuation teams, accusing Forbes of "intentional biases and inconsistencies" and bias against Middle East investors.
But Kingdom added it would continue to co-operate with the rival billionaires list of Bloomberg, which ranks Alwaleed 16th in the world with $US28 billion.
Alwaleed, 58, and a nephew of Saudi King Abdullah, owns large stakes of Apple, Citigroup, News Corp, Facebook and Twitter as well as a luxury hotel chain through Kingdom Holding.
Forbes argued in a long article published yesterday that it had sought to establish his wealth based on the underlying value of Kingdom's investments rather than the price of its Riyadh-traded shares.
Forbes explained that the share price has moved up sharply and inexplicably each year for the past several years just at the time Forbes researches its billionaires estimates, and the effect has been to inflate the company's market value far out of line with its intrinsic value.
It noted that Alwaleed controls 95 per cent of the shares, and few are traded actively over the Riyadh exchange.
Forbes described the prince as hounding and pressuring the magazine to use his own $US29.6 billion figure, "which would return him to the top ten position he has craved".
In the list out on Monday, Liliane Bettencourt, of the French L'Oreal cosmetics and beauty empire, was ninth with $US30 billion, and her fellow luxury tycoon Bernard Arnault, leader of LVMH, was tenth with $US29 billion.