Russian President Vladimir Putin has amassed a massive fortune, potentially the largest in the world.

International Business Times pointed out on Wednesday that Putin's fortune could be as much as $200 billion.

But Putin has been snubbed from official world's richest lists in the past, such as Forbes.

"We value individuals' assets–including stakes in public and private companies, real estate, yachts, art and cash–and take into account estimates of debt. We also consult an array of outside experts in various fields," Forbes wrote in 2015 , but noted that some individuals "cooperate" while "others don't," and added that the magazine excludes "dictators who derive their fortunes entirely as a result of their position of power."

Forbes did not stipulate that was the reason for his omission, however.

Time Magazine reported similarly in January, citing estimates from $40 billion to $70 billion.

"I believe that it's $200 billion," Bill Browder, author and a former fund manager in Russia, told CNN.

"After 14 years in power of Russia, and the amount of money that the country has made, and the amount of money that hasn't been spent on schools and roads and hospitals and so on, all that money is in property, bank--Swiss bank accounts--shares, hedge funds, managed for Putin and his cronies," he added.

Browder's personal website notes his antagonism toward the Kremlin. He prominently displays a book review from The Daily Beast: "Bill Browder was a high-flying businessman in Moscow, until Putin turned on him."

But Browder is not alone in thinking Putin is the world's richest, even richer than Bill Gates, Microsoft founder and philanthropist. Gates, officially at least, ranks No. 1, according to Forbes' latest list , with a net worth of $75 Billion.

Former Kremlin insiders have backed the spirit Browder's of assessment, but have shied away from specific estimates.