You have to post proof when you are making such a big claim. 500.000 BTC is a lot of money and it looks like you are making things up in your head. I doubt people in here is saying "im going to sell specifically X amount of BTC" and you have done an study to sum all of these potential sales into a big round "500.000 BTC" number. Sounds pretty dumb actually, that's why your threads my be removed as baseless FUD. At least post it in speculation where it belongs, otherwise you come across as yet another kwukduck.
That's really a huge amount of money if you have to think about it and I think it was just a huge speculative idea, which I think they couldn't provide us any proof. I think the statement was quite non believable, and as a matter of fact we shouldn't consider this type of FUD strategies to create doubt to people that misleads or diverts everybody's motivations. This absolutely makes the problem of bitcoin price to get worsen right now, and if this group of people will persistently appear to be aggressive in doing such tactics to manipulate the downtrend value of bitcoin, then we must break it and protect the entire bitcoin community from disruptions.