The Labor Department wants to double the minimum wage for making someone work free overtime. Union contracts supercede all this, but for the majority of Americans who don't have unions, the Labor Department sets the rules for overtime.
Let's begin by defining the terms supervisor and manager. A supervisor must have people to supervise, but a manager may simply manage resources. Whether someone is a manager turns on how much authority they have to spend money without clearing it with someone else. A key determinant is the authority to authorize overtime for workers without permission from a supervisor, ironic because supervisors and managers typically don't get overtime themselves.
The Labor Department, however, requires overtime eligibility for someone making less than 24 grand a year, and now says it will double that to 50 grand in one month's time.
For most companies this won't be a major issue, but companies that gave low-paid workers minimal managerial responsibility to avoid paying them overtime may find they have to do it now.