I'm not justifying it, but at most companies a budget is set for a team. Most CFOs rule with an iron fist and so any money for raises comes from general budget

I'm not justifying it, but at most companies a budget is set for a team. Most CFOs rule with an iron fist and so any money for raises comes from general budget raises. As a manager it's your job to wheel and deal within that constraint. Eg turn a vacant role into a less senior position to free up budget for keeping a valued team member.