I had the same thing happen recently, being rehired under subsidiary company, and they were great at explaining why (at least in a general sense) and reassuring

I had the same thing happen recently, being rehired under subsidiary company, and they were great at explaining why (at least in a general sense) and reassuring us it had no effect on our job security. We had to lay off a new hire and reduce hours across the board due to Covid-19, and once again they did a great job at reassuring us they had every intention of keeping (the rest of) us employed as much as possible.