My initial question was how did he sell $1B and not affect the share price substantially. And sure enough, the share price did drop a bit. But average trading volume is about 2 billion shares, which is about $2B. It's pretty crazy that the market has so much liquidity that $2B of AMZN changes hands every day, and that it could soak up a $1B sale and barely change the price.
Because of the order type. Market Orders soak up all the liquidity as they need to be executed at the best price available. So, if the price is at $10 and I dump a huge amount of shares, it will go through the bids..$10, $9.9, $9.8...you get the idea. Limit Orders kind of provide liquidity. It doesn't execute unless a certain condition is met. So I can dump a large sell at $10, it won't change the price. Anyone in th…
Conversely if I place a $1B sell order for $1100 (ought to be close to what happened here) the price cannot rise above $1100 until that amount of money has been extracted out of the market.