Your description of your company sounds like it might be more of a transfer pricing issue than an antitrust issue. If the companies all have their own tax situa

Your description of your company sounds like it might be more of a transfer pricing issue than an antitrust issue. If the companies all have their own tax situations, then transactions between them need to be "arm's length" so that income isn't shifted from one company to another without the proper entity paying tax on it. That's generally the reason for companies under the same umbrella charging for things. I think you're on to something about the competitive advantage that comes from those fees though. Matt Levine (who writes for Bloomberg) often mentions how odd it is that it's illegal for, say, two plumbers with their own companies to get together and agree to set their prices higher, but it's perfectly legal for those same plumbers to form a company together and then set their prices wherever they want. What's "anticompetitive" for two individuals is ok for a firm, unless the firm gets too big... It definitely makes you wonder if the definition of too big is actually set too high.