Seller is most likely Entek as the sell amount of 10 200000...

Seller is most likely Entek as the sell amount of 10 200000 corresponds exactly to their holding. They slipped under the 5% substantial level back in April due to dilution so would not have to notify ASX of any further selldown. Entek acquired this stake out of the Gulf of Mexico deal and as their business is oil and gas exploration ,SYS would be a non-core holding . DEREK or any substantial shareholder or director would need to of notified the ASX of this sell down so clearly it wasn't them.More important and positive is that someone thinks investing $500k into SYS is a good thing. If the acquirer does not own existing stock then only needs to purchase an additional 200 odd shares to take them to 5% at which point they will have to disclose who they are.Of course if they had an existing position , that purchase (asuming it went to one entity) would surely push them higher than 5%. The other possibility is that the buyer may wish to remain under the radar and therefore 5% for now to allow further accumulation in other entities without flagging interest particluarly if it would be likely that disclosure of the buyers identity would cause the market to pay attention????