I covered this in a different reply. It's not whales. No whale in his right mind would do that. If whales are buyers they would buy slowly and quietly on bad days. Any attempt by a whale to sell part of a large position would quickly move the price down. Imagine if the Fed was buying and selling gold. Do you think they could do a pump and dump?
In my opinion it is some newcomers to steemit who want to get in to SP and were panicked into moving faster than expected by a price rise. The rest are speculators who are betting the trend will continue.
I find it strange how 10.000 people ( that's the new active users in the last couple of weeks) can double the market cap in just a couple of days. We are talking about a 700 million dollars increase in market cap in just a few days. Also the 24 hour volume increased by about 80 million. If you divide 80 million by 10.000 you get 8.000 dollars per new users. That's a lot of money no matter where you live. Let's say that a lot of that money comes from speculators. Even an average of 1000 dollars per new user is a lot to invest in something you don't even understand.
I hope you're not annoyed by my insistence on this subject :) I just think that larger forces are preparing to capitalize on something big that is about to happen and the numbers paint that picture.