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SLA currently manages the assets for Lloyds' insurance and wealth units.
"We are disappointed by this decision in context of strong performance and good service we have delivered for LBG, Scottish Widows and their customers," Keith Skeoch and Martin Gilbert, Standard Life Aberdeen's chief executives, said in the statement.
A source close to SLA said the mandate represented around 5 percent of total company revenues.
SLA will take a one-off impairment charge of 40 million pounds following the cancellation of the mandate.
Lloyds and Scottish Widows said they had begun an assessment of the market to identify a new manager of the assets.