28% decline is an extreme event that shows a major issue has...

28% decline is an extreme event that shows a major issue has been encountered. In this case, selling immediately helped you preserve some capital that would otherwise be lost if you had held, and so congratulations. Of course, events like this usually result in an immediate over-reaction that is then followed by an increase in the share price from its low once people have had time to evaluate and put the matter into perspective. Nevertheless, the subsequent bounce may then be followed by a more gradual decline as the wider market makes a more informed assessment as to the impact and likely period of time before the company can regain a positive momentum. Equally, the SP may hold around the "bounced" level if there is confidence about the overall business and its prospects, or even increase further in a slower manner.
Every situation and every company is different and so you need to consider all the information that is available. Additionally, every investor's situation is different and so you will need to make your own decision accordingly.
The shock factor of an unexpected announcement like this almost always results in an over-reaction and so if you are a short-term trader then you might buy and then sell again quickly on the typical bounce and make a quick profit. Whether the SP trends back down afterwards, depends on the underlying business and situation. Nevertheless, if you buy in again as an investment, then you will probably need to wait for some time for the SP to recover, which means until the company shows that it has overcome the bad situation and can again produce profits in line with previous results.
Sorry to be general in my comments but I am not prepared to advise on the specifics of SIV except to say that I have lost confidence in its management as a result of its announcement today.
In general, shortage of news is not a sign of problems but may simply mean that management has nothing of significance to report. In this case, my expectation is that the Board advised the market once they had made a firm decision; until then it was still a "work in progress".
Personally, since you are an investor and not a short-term trader, I would wait a bit before buying in again and assess any analysis and nformation that comes your way. Nor would I expect a quick recovery to the previous SP, even if in the longer term SIV proves to be a good investment.

All of the above is a purely personal view and not based on any private information unavailable to others. everybody needs to make their own assessment based on their own circumstances.