Fairly common process in corporate America.
It starts at the top - they determine how much $$$/labor expense they want to reduce and in the process this is translated into head count. Then the ripple begins, the head count number is cascaded down the ladder breaking down as it passes each level. Business line head is told to cut 100, then they break down that number to their direct reports, and the process repeats at each level going down.
Then when it hits the lowest management level the business line wants the buck to end which can be your immediate manager, 2nd level manager, or 3rd level manager at that point a list is created with names then that list is sent back up the same ladder. The manager at each ladder rung combines the list and tweaks as appropriate such as potentially adding one of their direct reports.
This process goes up to the business line or divisional head. If the list is all good and meets the $$$/% target then the list goes to legal/HR for vetting and planning. Once the ducks are lined up then a date for layoffs is set.
There are variations of course but this is the general idea.