This is the statement of the US Treasury Department on its intention to take harsh measures against financial institutions for money laundering using cryptocurrencies, and the introduction of US sanctions against 28 cryptocurrency bitcoin addresses, which are accused of involvement in interference in last year's presidential election, and a statement by the Turkish government to ban use cryptocurrency as a means of payment, and other similar news.
Huh. I hadn't heard about any of that--and I probably should start reading some of the crypto news sites regularly instead of relying on members here to post about something. But whatever; I'm not sure any of the above had anything to do with the price drop we saw over the weekend. JackG's explanation seems to make more sense, although whenever I see bitcoin drop 10% or so over the course of a day or two, I usually attribute it to traders selling bitcoin and taking their profits.
OP probably hasn't been watching the bitcoin market for a long time, because if he had been he likely would not have asked this question. Bitcoin has been far more volatile than it was this weekend, and a lot of times there's absolutely no explanation for the price movement. It's all about investor sentiment--the demand portion of the supply & demand curve. Sometimes people just sell a lot of bitcoin when there aren't enough buy orders to keep the price afloat and what happens? Bitcoin drops. I've learned to just accept the fact that bitcoin is crazy volatile and very unpredictable. That's what makes it fun!