Stories of incompetent managers (and/or accountants) who take out their frustrations on their work-force are, of course, the stuff of legend. (Which has little to do with the process of “performance appraisals.”) If a company believes that it has hired 10% too many people to do the job, it is probably wiser to fire the one
damned fool person who is saying that. However, if that person appears to be attracting a sincere audience, it simply means that the company has cash-flow problems ... which are almost always endemic. The bloodstream of a business is cash, and “congestive heart failure” is always fatal to it.
“Substantial layoffs” are, pure and simple, a sign that there are icebergs in these waters, and that the company has recently hit one of them. (It is very easy to <!>-up a company, even when management didn’t mean to.) The company doesn’t have enough cash to pay its bills, and probably has tapped-out its lines of credit or is well on its way to doing so. It is deciding whether to cut off its arm or which one of its legs. If a major company makes substantial hits to its data processing operation, in particular, then that is a company that is “going down,” no matter how long it actually takes to hit the ground. (If cash is the bloodstream, then the digital computer is the heart and hands and feet.)
You might not have the privy data with which to make a decision, but you can always see the signs. Don’t sit there in your comfy seat, waiting until you actually smell smoke. If you are reasonably alert and attentive and educate yourself as to what to look for, you can usually spot the warning signs months or years ahead of time, while management is still (publicly, at least) in denial. If the words on that wall aren’t graffiti, don’t let the door hit you in the butt. Don’t spread secrets or spill (or buy stock or puts/calls based on) what you may know; just carry your own box of personal belongings out to your car.
All that you can do – all that you have to do (unless you are an officer of the place, you unlucky SOB...) – is to get out of the way. There will always be very strong demand for people who can make a digital computer sing and dance: if not “here,” then “there.” This is the way that business actually works. Don’t take it personally, and try not to get caught by it more often than you inevitably will. You are a very well-paid employee; therefore, you are very costly. It is merely a contract; no one owes any allegiance to anyone. It’s par for this course. Plan wisely.