alt Hacker NewsThis is bad. If they came out announcing this, without a long winded explanation and further details, it's because they're staring at a bottomless pit and they haven't put the lid on it yet.
For a Fortune 100, to go out of your way to spook investors is the least desirable approach.
Letting people know promptly is also the right thing to do and probably mandated by (at least some) customer contracts. You can't tell just some people; it would leak anyway.