Re: Not again!
"they are all employing you, contract or not."
Not in this context. "Employ" has a specific meaning. It means that the person employed is an employee. Even if you start thinking in a more generic way such as "We employed a waterfall development approach" as soon as it's a person you're thinking about you're probably half way to coming to the narrow conclusion without even giving the matter due consideration. Worst of all, in any sort of tax investigation if you use the term in the loose sense to an inspector or a tribunal it'll be leapt on and taken literally.
To help you understand lets say ClientCo has 50 workers bodyshopped in by BigCo amd one worker bodyshopped in by LittleCo which he happens to own? Would you say the 50 are employed by ClientCo? Say the project was wound down and there's only one worker now bodyshopped inby BigCo; would you say they were employed by ClientCo? If BigCo's employee isn't employed by ClientCo why is LittleCo's employee?