The World: Miami - MDC rumoured to raise shareholding in Crispin Porter

The future ownership of the Miami hotshop Crispin Porter & Bogusky is in question amid reports that MDC Partners, Canada's largest ad group, may move to a majority shareholding.

MDC has the option to raise its stake in the agency from 49 per cent to 60 per cent this year, and to 77 per cent in 2008. Miles Nadal, the MDC Partners chief executive, insisted he would not try to increase the group's stake in Crispin Porter without its co-operation.

Jeff Hicks, the Crispin Porter chief executive, said: "It's not MDC's style to make unilateral decisions about its agencies."

The agency has denied rumours that it is looking to buy itself out of MDC.