But a large broker house exposing themselves to inside trading...

But a large broker house exposing themselves to inside trading seems completely outlandish.

It's not outlandish at all, it's the norm. Insider trading is not a black and white thing, so very difficult to prove and in many cases by the letter of the law not classified as insider trading.. There are many ways to use information that is NOT freely available to all to manipulate with. A lot of information is presented for example when organising placements. I've seen term sheets in the past (not referring to DUO here) with information I am amazed is not in the public domain.

If there is a pump it will most likely come on the back of a new investor presentation and a research report from Patersons.

Sure this might be part of a pump but won't drive a share price on its own, it needs the real (or implied or misguided) associated news.

Not because of some good news that ZYB could release now but Patto told them to hold off because they need that news for the pump.

Not suggesting there is any news they could release now and holding onto, but they will have a clear plan on when this will most likely occur, maybe based on already known timetables etc etc and yes they will hold it till they're ready. Bottom line is once the information is available the release will be timed to suit.