The appointment by the Treasury is designed to increase public awareness of the range, which includes a modified stakeholder pension, child trust fund, investment product and deposit account.
According to a Treasury spokesperson, MCBD impressed with the quality of its research and thinking.
"The team did a great job on the day and we look forward to working with them alongside the Department of Work and Pensions and HM Revenue & Customs over the next few months to develop this campaign," a spokesman said.
MCBD won the account after a pitch against M&C Saatchi, HHCL Red Cell, Mother and DLKW.
The Ingram Partnership went up against Naked, ZenithOptimedia, PHD and Starcom MediaVest, for the work in an open pitch managed by the COI.
The win for MCBD comes after it topped the media section in this year's Sunday Times list of the 100 Best Companies to Work For.
Recent work includes the hard hitting domestic violence campaign for the Metropolitan Police.
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