The company had earlier warned that it was not going to meet full-year earnings estimates, and has seen its rating cut by the investment bank JP Morgan.
Interpublic said that earnings per share were likely to be between 8 and 10 cents a share, compared with analyst estimates of around 28 cents a share.
Shares dropped by more than $6.30 today as investors reacted to the news. The previous low came in August, when Interpublic said that it had to restate its last five years' results after $68.5m (拢44.1m) was improperly booked as income. The company now faces numerous lawsuits from shareholders as well as an investigation by the SEC relating to the discrepancies.
Interpublic, which owns advertising agencies such as McCann-Erickson and Foote Cone Belding, has said that its earnings have been hit by problems at its sports marketing agency Octagon and economic problems in Latin America and Japan. It says that earnings for the full year are likely to be down 9%.
John Dooner, chairman and CEO, said: "It is regrettable that we have had to revise our earnings forecast, but this new guidance reflects the difficult economic conditions we are facing around the world.
"We are dealing with our short-term issues in marketing services aggressively and directly. Among our other operating companies, many of our brands are demonstrating competitive vitality, as evidenced by encouraging new business gains."
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