We have seen this happen a lot. When the price tends to go up a bit, a dump pops up making the price go lower again. At the moment it's only a few bucks, but it also happened when we were above $450. The price was dumped down to lower $400's shortly after that.
Truly selling your bitcoin at a price higher than $400 surely gives you a good profit, right now most had suggested to hold just for the reason of halving. On halving you might experience a very good profit than selling now.
People buy or trade for bitcoins in many different rates and selling for $400 each brings no profit to them. Everything 500 and up should be considered a small/good profit but i hope too that the price will be increased at the halving.