I've been following the actions of this whale for several years. He is a legend, making $100-200mil by leverage trading on BFX and other derivate exchanges. Since he is well known to the owners of exchanges, he can't openly manipulate the market. My observations show that he is working alone and he is a fair player. In that sense his shorts can't harm the price. Also, he was not always right. It's just that his successful trades are more important than the unsuccessful ones. For example, after 12 March 2020, when the price recovered to 6K, he was confident there will be a pull back to 3K. He failed miserably then, losing a big portion of his wealth. After that, he announced he is retiring. But clearly, he changed his mind recently, when he saw the 12+ consecutive red hours, repeating each Friday. He closed his shorts just before the price fell to 28K last week, fearing a strong rebound. He was right. Now he thinks the price will fall to 30K and is waiting with $800m+ shorts. I don't know what is the leverage, but by a pure speculation it is between 5x and 20x, probably 10x. I've noticed that he added his short positions after the price fell to 33K area yesterday, which clearly shows he is not involved in the regular dumps. Moreover, even if he dumps on BFX, it won't affect the price on the other exchanges. Nowadays Binance is forming the price and the huge volume there makes it harder for a single whale to manipulate the price. But there are other futures exchanges, so this is a valid possibility, of course. Especially, if we have a group of whales making coordinated dumps simultaneously on several exchanges.