Some people have been mentioning how I talked about a fairly low amount (a few millions) to manipulate Bitcoin so figure here might be a good place to clarify. It becomes easier to manipulate Bitcoin during sell offs and pumps because the order book tends to become thinner, which is the opportune situation for wealthy individuals (as proven with the Bitcoin Cash pump when it was listed on GDAX). 40 Bitcoin would probably be enough to do some damage if you used it properly while order books were relatively thin. But the big players tend to have over 100 plus an equally sizable amount in cash.