The broker said it was cutting its forecast for organic growth from 4.8% to 2.4%, based on higher investment costs and pressures on profit margins for Aegis, even when account wins such as New Line Cinema were brought in to the equation.
Shares opened at 82p, but by the afternoon had fallen by 6.5% to 75.5p at 3.10pm.
Aegis owns the media-buying agency Carat and the company is being lined up to be the consolation prize in the Havas Advertising and WPP Group fight for rival media-buyer Tempus Group.
Doug Flynn, CEO of Aegis, has stated on numerous occasions that Aegis will fight to remain independent.
However, reports have been emerging from within Aegis that there is pressure pushing the company towards WPP.
This morning, WPP increased its stake in Tempus from 22% to 26%. This seem to quash some speculation that it was only interested in pushing up the the price Havas would have to pay for Tempus, giving it a bigger profit.
Havas has extended the deadline for its Tempus bid for a second time. The new deadline is September 24.
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