They could also do a private party transaction to sell the coins outside of an exchange, in order to hide the sale and also hide the price of the tokens sold.
This is common practice in the stock market, called "dark pools" [0]
> Dark pools came about primarily to facilitate block trading by institutional investors who did not wish to impact the markets with their large orders and obtain adverse prices for their trades.
Outside, as in off the blockchain? That would mean that after the transaction, both sides would know the key to the wallet and there would be a race about who lights up a transaction first.
A large wallet that’s been dormant for years suddenly becoming active will tend to pressure the price lower from the implied increase in liquid supply and fear that the wallet will continue to distribute coins.
It’s not just the printing of transaction price that can affect the market.
While ~$8B is huge news, due to the potential that all ~$188B might be in play, when most investors probably expected it was not prior to this - or at least the probability was low enough to barely factor, it's unlikely to crash BTC.
Further, moving BTC is one thing. Showing signs of liquidation is another.
That much should be able to get liquidated intelligently without moving the market.
