According to a study by JPMorgan, quoted by FT Alphaville, the authorities may decide to retain the stock on a longer than temporary basis.
If this takes place, researchers behind the study predicted that the debt would be included within the UKâs net debt, which would lead to the UKâs debt to GDP ratio increasing from 64 to 165 per cent.
Carla Antunes da Silva, an analyst at JPMorgan, said: âAt the crux of this debate is the conflict of interest of owning large stakes in the banks whilst trying to implement significant regulatory changes in a global forum and balancing this with influencing banks' lending behaviour.â
The report also showed that the UKâs new coalition government is divided on what should be done with the two stakes.
Liberal Democrats are thought to want to retain the shares while Conservative members of the new authority are keener to see the stock sold.
The government owns a 41 per cent stake in Lloyds and an 82 per cent share in the Royal Bank of Scotland.
By Jim Ottewill