Go Long.

There is a chance that RBC had several people selling making up 250,000 as well as someone that decided to pick up those 250,000 shares. Remember that they make commission on each and every transaction and if the buyers and sellers are all within the RBC system they could care less, Its all money in there pocket.

You may be right that theres something fishy but if you have level II on SH , it will break down the 250,000 shares and tell you how many holders make up that sale.