TOKYO, Oct 11 (Bloomberg) -- Purchases of government securities by US, European and Japanese banks may remain elevated, following $1.1 trillion of additions of the debt during the past year, according to Barclays Capital.

The holdings ballooned 30 per cent to $4.6 trillion as banks "de-risked" balance sheets and boosted "super liquid assets," Laurent Fransolet, head of European fixed-income strategy at Barclays Capital in London, wrote in a report today.

While the buying will slow, according to Fransolet, at least some of the impetus for the acquisitions will probably drive continued investments after the worst financial crisis since the Great Depression and help restrain bond yields.