For example, let's say you are a whale with 100,000 BTC, currently worth about $350 million. Would you drive the value of your coins down by 20%, or $70 million, just so you can save $7 million when you buy another 10000 coins? Lose $70 million, but save $7 million -- sounds like a great plan.
People don't understand that there is more in this market than whales trying to manipulate the price to buy lower. I am sure that whales have done enough to support the price at certain levels to maintain their portfolio value, but it just wasn't enough with how severe the selling pressure was. Imagine if they didn't provide that buy support, we might have tanked way harder than what most people can imagine right now.
A lot of selling pressure came from ICO's, and what people seem to ignore, Bitcoin miners themselves. They have to sell more coins in advance in order to make sure that they have enough liquid funds to be able to pay their bills in the forthcoming months.