“Does FTC investigate or who?”
Actually, FEC, as in Federal Elections Commission.
And yes, if ANY Facebook resources were given (or shared, to use metrosexual language) with the Clinton campaign, that would be an ILLEGAL, in-kind, contribution. “In-kind” meaning not cash, but having the same value as cash, and Illegal because it’s simply ILLEGAL for any corporation, or any union, for that matter, to provide any material aid to a federal campaign without being paid fair market value. People from those corporations (or unions) are welcome to volunteer personally, or even get paid for work, but corporate assets cannot be used.
If Facebook turned over the profiles of their users to Hillary, they (and Hillary) are (or at least should be) in HUGE TROUBLE.
Actually, it will probably be the great Nobody that looks into this.