Massive can be defined in my eyes as any holding being several...

Massive can be defined in my eyes as any holding being several times larger than the daily traded volume for a simple reason: It can influence the movement of the stock significantly on the short term, when the position is sold, be it in one order or piece by piece.
Imagine a person trying to sell, let's say up to 2.000.000 shares. Not that many shares at all and currently worth just 560k AUD. But what will happen to the stockprize with current daily volumes ranging from 20.000 to 150.000 shares?

And by the way: I will tell you what is REALLY stupid in my eyes: Giving advice to people to either sell or buy a stock. Laughable. I will for sure not sell or buy anything based on opinion of any clueless person x in the internet.