erm yes there is? all related party transactions must be of fair market value
Which rule is that? I don't think the accounts are required to show related party transactions at fmv, but the PL has the right to adjust to fmv for FFP reporting purposes. Anyway, it doesn't matter.
Firstly, none of Etihad, Etisalat, Aabar, ADTA, Fordham, Mancini or Toure (which are apparently the target of the most serious allegations) are related parties, unless the PL is questioning the definition in the accounts, which would be a stretch as even UEFA didn't try that.
Secondly, on sponsorship, as far as I am aware, the fair value isn't being questioned. It certainly wasn't by UEFA at CAS and it hasn't been questioned in any of the years since 2009 by the PL, as far as I am aware.
Thirdly, the allegation with the AD sponsorships is that Mansour secretly funded the sponsorship commitments, deceived the auditors about the source of the sponsorship, filed accounts knowing them to be wrong, and then knowingly concealed these facts from the PL. Nothing to do with fair values.
The point of my post is that there is no rule saying owners can't fund sponsorships in the same way there was no rule (at the time) saying the club had to report all remuneration a manager received while under contract to the club.
But that doesn't matter. The allegations in the first tranche of allegations are that the club knowingly overstated income (sponsorship income) and understated costs (presumably Fordham, Mancini and Toure) in its filed accounts.
That is the actual situation, afaik, but I really don't have the energy to go through it again.