Visit https://www.gdax.com/trade/BTC-USD https://www.gdax.com/trade/BTC-USD. Notice the v-shaped graph below the price graph. Hover over to the left on the gree

Visit https://www.gdax.com/trade/BTC-USD https://www.gdax.com/trade/BTC-USD. Notice the v-shaped graph below the price graph. Hover over to the left on the green side. You won't have an answer to your largest-ever-on-HN question, but right now I can tell you these are all possible (picking random zoom levels) with the quoted price around $18,100: You can sell 556 BTC for $9.949 million for an average price of $17,893. You can sell 2,160 BTC for $37.4 million for an average price of $17,314, which is 95.6% of the current quoted price. This is if you are a complete idiot, transfer your Bitcoin to GDAX, and place a market sell order. Maximum slippage, and yes, you'd temporarily tank the GDAX market down to $16.5K or $17K. And it takes a while to withdraw that amount of money from Coinbase, but eventually it happens, and your trade is already complete. Anyone with an ounce of sense would instead sell their BTC in a number of limit-order chunks over a day or two to reduce slippage. Now, you can keep saying that it's a "common misconception" that the last ticker price means anything. Technically you are correct. But I doubt the guy who just liquidated BTC for over $30 million USD at 95% of that price would care.