For what it's worth, my limited experience in other stocks that...

For what it's worth, my limited experience in other stocks that may be relevant to your theories:

- When there was some kind of rule violated - typically an ASX requirement - I have seen suspensions this long, but it certainly wasn't a 'technical update'. By memory, the ASX actually put out the announcement themselves, as well, so I don't think you can actually put that on the list for speculation.

- For acquisitions (this is non-tech stocks in my case - no wait, one was a software company, so I guess that's tech.), there was no trading halt or suspension over 'discussion and negotiation', and the announcement that didn't exist was again not called 'technical update'. The actual offer had a trading halt, just a standard, full length trading halt, here's the offer, it looks good (and your piddly shares wouldn't be enough to affect the outcome anyway), so we are on our way ... like 6 months from now. The announcement, again by memory because I CBB, was called something highly relevant, I believe it was 'commercial transaction'. Anyway, the offers were generally tied to the SP, usually around SP+10-20%, but they were firmly in the category of 'smart strategic decision' transactions that came in a quiet period when both companies were looking for ways to grow, so categorically different from this. There was a mining stock that I stuck a toe in but didn't like the water that got bought up a bit later, again it was a trading halt, here's the offer, but it was something like a 3x jump in price because they found something (I don't regret this, though - as many times as this happens, 10 other mining companies just soil the bed; it's just gambling).

In short, at the very least the announcement so far isn't an acquisition, as far as I can see, and they don't have to tell us if they just showed the technical update to interested people, they don't have to tell us if people are interested, and they don't have to tell us if they are talking to interested people. They may want to! That's probably a good idea. But it's not a trade-halty idea

- For having no reason for the suspension, remember that they don't actually get to give themselves an extension. The ASX has to review it, and 4DS isn't Telstra - they can't call in any special favours for this. Whatever it is, they had to tell the ASX and the ASX had to be satisfied. You aren't at risk because you can't sell your shares, because there's nothing intrinsic to buying shares that you have to have the opportunity to trade them whenever you feel like. That is called 'a bank'. Just ask Evergrande investors about this, this is something they know a LOT about. They do have to have a reason for the halt or suspension that satisfies the ASX, they do have to give you the opportunity to trade if any other person anywhere has the opportunity to trade, and they have to ensure that no one that can buy or sell the stock has access to less information from them than any other person that buys or sells the stock. That last point was the burn for me when hearing of that director sale from a year ago.

So where I am, as a person whose thing is communications and law (but not business law), I keep thinking of the ASX rather than 4DS. What would ASX allow these suspensions for? Sign off from an external is a good bet, a really solid bet, and it takes up to a long time, but that would only be the case, absolutely only be the case, if the sign off was for something that put some form of pressure on one of the signers off. That could be liability, where, for example, 4DS wants to say this thing flies to the moon and points to results for IMEC; if a purchaser wants to buy the company on the information from IMEC, then the product doesn't work as described, IMEC is suddenly on the hook for a rather large bill. The ASX would definitely be okay with that; they'd almost have to be automatically within reason. Other options are constrained by the 'technical update' header, but it could be something along the lines of interfacing with new facilities for further development, which other people have pointed out would most likely have to be something like Samsung or Kioxia, and then again you need sign off to say if this is even possible, you know, can this fab even do the job, so then you have people swapping designs, checking their machines. The ASX might be okay with that.

The substantively worse options, where maybe it's abandon ship and stuff, the ASX would, from what I can see, not be okay with that. Not to where the people in 4DS are getting so much room to position their strategy, about a month, and the stock standard trader gets no information, and the ASX agreeing that that's okay not just once but 4 times (including trading halt). That, to me, is really improbable.