I lay point of view............

The way I look at it is that a stockholder no longer believes in the company so he is selling. The other side is that someone, either a current shareholder or a new potential shareholder is buying which convey's that they believe the investment will be rewarding.

I look at the determination as to buyer or seller based on has the price decreased or increased by a enough margin to justify one of the definitions. If there is basically no movement in the price, then it is difficult to determine any difference between a seller or an accumulation or a new buyer.

Really doesn't matter what you call the trade, it's a matter of has the price increased?