Ownership concentration has become a commonplace problem in the cryptocurrency market - but even this is extreme.

We've reported on bitcoin's whale problem, where roughly 40% of all the bitcoin in circulation - an amount worth some $51 billion - are held by a group of less than 1,000 people, many of whom were among the earliest adopters.

In fact, it's widely believed that bitcoin founder Satoshi Nakamoto alone controls a combined 1.1 million bitcoins (though it's impossible to discern an exact number).

Ethereum is even more concentrated, with 40% of the total float owned by 100 people. But even Ethereum pales in comparison to Block.one, the largest ICO in history, which raised more than $4 billion last week.

According to Bloomberg, the 10 largest Block.one owners hold nearly 50% of coins in circulation.

The largest holder is the company itself, with 10% of the total. This situation mirrors that of Ripple, which was criticized earlier this year when CEO Chris Larsen briefly saw his net worth eclipse that of Mark Zuckerberg when ripple rallied 1240% in the span of a month, briefly making it the second-largest cryptocurrency. Larsen alone held a 17% stake in the company, raising hackles about the ease with which he and other ripple founders or early adopters could influence the price in their favor.

And it's likely traders will soon begin sharing similar warnings about Block.one, as the token's price rallied 13-fold.

Though they have smaller market caps, the coins Qtum and Storj are even more concentrated than Block.one, with the top holders controlling 90% of the coins in circulation, according to an analysis by Tetras Capital.