Omnicom executives have spent this week in intense negotiations with Euler Trade Indemnity, after Euler warned it would withdraw the insurance coverage it offers to media owners dealing with Omnicom from this Friday.
Such a move could expose media owners to losses in the unlikely event that Omnicom should fold.
According to Anthony Wreford, Omnicom's head of Diversified Agency Services Europe, eleventh-hour negotiations by Omnicom's chief financial officer, Randy Weisenburger, have convinced Euler to defer its decision until after Omnicom's half-year results next month.
The notification threatened to forestall the recovery that Omnicom's share price has achieved in the past few days.
The news met a concerned but cautious response from UK media owners.
Last Friday, the Newspaper Publishers' Association circulated an e-mail to members warning them of Euler's decision but stressing that it did not recommend any course of action to its members as a result. Associated Newspapers and Trinity Mirror are both understood to hold insurance from Euler for dealings with Omnicom.
The ITV Accreditation Committee has also been made aware of the notification, but ITV and the NPA were not willing to comment.
Euler's threat follows allegations made by The Wall Street Journal on 12 June about the validity of the group's accounting practices. The paper alleged Omnicom had misleadingly reported growth in "organic revenue that included revenue generated from recently acquired companies, failed to disclose future earn-out obligations and avoided writing down the value of internet investments by transferring them to a new entity. Several US law firms have filed shareholder lawsuits against the group.
On Monday Omnicom issued a defence via a 48-page report posted on its website. The US credit rating agency, Fitch, gave an A credit rating for the group on Tuesday.
Weisenburger conducted phone negotiations with Euler executives on Tuesday to request a reconsideration in the light of these developments. Euler declined to comment as Campaign went to press.
"Omnicom has ample liquidity to meet all foreseeable business and capital requirements, Wreford said.