The Financial Services Authority (FSA) is close to concluding its inquiry into alleged mis-selling by RBS-owned wealth manager Coutts.
The regulator could finish its year-long probe into the sale of an AIG bond fund by Coutts in the autumn, according to Sky News.
In a statement last August RBS said the FSA told the bank it was beginning an investigation into the sale by Coutts of the ALICO (American Life Insurance Company) Premier Access Bond Enhanced Variable Rate fund to customers between 2001 and 2008.
If the watchdog finds evidence the ALICO-branded bonds were mis-sold it could impose a substantial fine on the wealth manager.
Sky News sources said initial indications from the FSA's inquiry suggests there are grounds for complaint.
The dispute over the sale of the bonds gained prominence in July 2009 when founder of the Air Miles and Nectar loyalty programmes Sir Keith Mills launched a national ad campaign to publicise his grievance with Coutts.
He subsequently established the Coutts Action Group to raise awareness of the oversight.
The FSA declined to comment.
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