Let's say my company hires a contractor. They work on revenue share. If there is not enough revenue to where their share would be greater than or equal to minimum wage, is the company required to cover the difference? What if this is a full-time employee, opposed to a contractor?
Anyone who is an employee as defined in the federal Fair Labor Standards Act of 1938 (FLSA), 29 USC 201 et seq.(or parallel state minimum wage laws) and is not within the scope of an exemption to the minimum wage law, must be paid minimum wage.
The relevant question is whether or not the person is an employee who is not exempt from the minimum wage requirement as defined in the FLSA. The question is a mixed issue of fact and law in which the characterization given to the relationship by the company and the person doing the work is one factor, but not the only or the controlling factor, in determining employee status.
The exact nature of the work governs whether the FLSA's minimum wage requirement applies or not. For example, "employee" is defined for puroses of the FLSA at 29 USC 203(e) to exclude "any individual employed by an employer engaged in agriculture if such individual is the parent, spouse, child, or other member of the employer’s immediate family" and certain kinds of volunteers. Piecework pay is allows under certain limited circumstances by 29 USC 207(g) when the usual result is that reasonable workers earn the minimum wage. Tipped employees (which is a form of revenue sharing) also receive special treatment. Most of the exemptions are found at 29 USC 213. Most relevant to your question is 29 USC 213(a)(1) which includes an exception for an "outside saleman" who is paid on a straight commission basis, and 29 USC 213(a)(5) and (a)(6) which contain exclusions for certain farming and fishing occupations.
Straight commission compensation without regard to the minimum wage is generally not permitted with regard to an employee who is an "inside salesman" (e.g. someone who works at a retail store in a mall or at a phone bank for a telemarketing company), or for anyone other than an outside saleman in non-agricultural jobs.
Independent contractor status generally depends upon the degree of control that the company has over the manner in which the work is performed, the assignability of the contract to do the work, and the extent to which the worker does work for many different companies on a contract basis while complying with employment related laws for the contactor's own employees (e.g. worker's compensation). The working for many different companies on a contract basis prong of the test is frequently controlling in practice. Six of the main factors considered by the Labor Department in determining independent contractor status are discussed in Fact Sheet #13.
A true independent contractor may be paid on a revenue sharing basis without regard to minimum wage, although in practice, if this results in the independent contractor earning less than minimum wage, there will be strict scrutiny of the practice. Typical independent contractor arrangements that would be allowed would include an attorney working on a contingent fee basis, or an independent broker or realtor working on a straight commission bais. More often than not, a true independent contractor is someone you couldn't even imagine being an employee subject to minimum wage laws of the company in light of the overall relationship and often this will involve a business to business contract, rather than a business to a non-professional individual contract with only personal services involved.
There are some safe harbor provisions that if met can insure independent contract status, but it is very common for someone who legally is an employee to be misclassified as an independent contractor in an attempt (often futile if the matter is pressed by regulatory or tax officials) to avoid compliance with laws incident to the employment relationship.