Selling ~7M ETH is easy without affecting the markets too much. Kraken and Poloniex each do an average weekly volume of 3M ETH on the ETH/BTC pair: https://cryptowat.ch/poloniex/ethbtc/1w If he spread the sale over 10 weeks he would only increase their weekly volume by 10%.

That's not even talking about alternate ways to transfer his wealth out of ETH (eg. approaching his billionaire friend: "how about you sell me that mansion for 100k ETH?")

It will affect the market. The weekly volume is irrelevant because that is gross sum of all trades taken place. What you are proposing is that he occupies nearly 23% of all "asks" on these exchanges which will be difficult to achieve.

And again off exchange block/bulk sales tend to go for lower than market price. They are rarely, if ever, executed at market price. So most probably he will have to offer 100k ETH, 4.8mil, for a ~4 mil mansion.

Sell also on the ETH/USD pair. Sell on a 3rd exchange. Lengthen the sale to 15 weeks. And he will be at 10% of all asks. 1 in 10 ETH sold being sold by him would hardly "tank" Ethereum as Pxtl was implying.

"4.8mil, for a ~4 mil mansion" I agree and that's totally reasonable. Only a 20% hit. Pxtl was saying something much more dramatic ("he'd never be able to get a decent fraction of its worth").

That's a problem for any substantial wealth in securities. Also why Wall Street stock and bond traders exist.

> owner of a substantial fraction of the blockchain

No, the blockchain is the data structure that stores historical transactions.

He could be a large owner of the circulating currency, and he would face issues trying to sell a huge chunk of value all at once. The crypto markets are not very liquid compared with mature financial markets.