The two investors purchased interests in FGP TopCo, with Ardian taking a 22.6% stake and the PIF a 15% cut.
The New Jersey-based transportation workers pension fund is in critical status, according to the Pension Benefit Guaranty Corporation.
Arctos Partners and Ares Management will take stakes in the Bills and the Dolphins, respectively, following a landmark August decision that permitted PE investments in the football league.