• by David Goetzl  @dgoetzl, June 4, 2009

With uncertainty still swirling around the implications for Publicis Groupe of General Motors' bankruptcy filing, the holding company said Thursday it could lose up to $78 million in the matter.

Earlier in the day, Standard & Poor's said it would be monitoring Publicis' credit rating in light of the GM action for a possible downgrade.

Based on Publicis' disclosure, it appears that GM's media vendors -- including networks and newspapers -- may be owed approximately $70 million, or more.

In court documents that GM filed this week, the automaker said it owed Publicis nearly $150 million.

Publicis' Starcom MediaVest Group (SMG) unit was listed as being owed $121.5 million-- and as the sixth-largest unsecured creditor, while Publicis itself was listed separately as being owed $25.3 million.

SMG buys all media for GM; Publicis agencies such as Digitas and Leo Burnett perform other services.

Of the up to $78 million that GM may owe Publicis, the holding company could reclaim some or all of the amount if it can obtain "essential vendor" status for various entities. Publicis referred to that amount as its "maximum exposure" financially to the GM turmoil.

MediaPost reported Monday that Publicis CEO Maurice Levy had indicated to investors that "any money collected from GM would go directly to Publicis; it doesn't need to be passed onto media companies where it purchased inventory on GM's behalf." Publicis said Thursday that is not the case.

Through "sequential liability," Publicis said SMG acts as an agent to make media purchases on GM's behalf. In the case that SMG has not been paid by GM for purchases made, the liability to pay the vendors lies with GM and not SMG.

It appears that GM owes SMG approximately $70 million, which SMG would then pass along to vendors.

Earlier Thursday, Standard & Poor's said it would track Publicis over the next 90 days before determining whether to downgrade its credit rating from a BBB+, although the rating agency did say it does not anticipate that will be the "most likely outcome at this stage."

S&P cited several risks facing Publicis, including the possibility that GM could "discontinue its contract with Publicis," while the holding company "could sustain substantial losses on its outstanding receivables from GM."

Publicis said Thursday it expects to continue working with GM as the restructured company is formed, and after.