The former director of the US government agency that insures private sector pensions has been accused of "inappropriate contacts" with Wall Street companies bidding for contracts to manage up to $2.5bn of the agency's assets.

Charles Millard, former director of the Pension Benefit Guaranty Corporation, was found to have called and e-mailed executives at Goldman Sachs, BlackRock and JPMorgan Chase, among others, while he was evaluating bids from the groups to manage assets last year.