With all of the recent layoffs that HP has had, I'm glad I'm no longer there. Working directly for GM feels considerably more secure than HP ever did. As others have said, I suspect it was an easy way to shed a bunch of employees without having to pay severance.

Probably preferable to layoffs (cheaper, no bad press) if a major project is shutting down and they have nowhere to put them.

Also, could have been wrapped up in all sorts of other agreements about termination of contract. This was probably a major deal for both companies.

Simple for the employees changing employers; whatever GM did to facilitate the transfer has not been made public.