Bithumb is one of the fifths largest exchangers currently on the Coinmarketcap list, but it looks like the raid by the South Korean police that happened a few days ago is certainly a big blow to them and also their users, I personally have made several transactions on the Bithumb exchanger  during This, and in my opinion so far Bithumb has not had a problem at all because every time I process transactions quite fast, but  so I never keep my money or assets in one wallet exchanger for a long time because it is too very risky and honestly, no matter how big exchangers no one is safe at the moment.