Former UBS general counsel David Aufhauser, who resigned last year following allegations of involvement in the bank's alleged sale of auction-rate securities, has rejoined his former firm Williams & Connolly.

Aufhauser – a former managing director of the Swiss bank and general counsel of the US Department of the Treasury – last October settled charges with New York attorney general Andrew Cuomo that he engaged in insider trading at UBS, agreeing to pay $6.5m (£3.9m).

As part of the settlement, Aufhauser also agreed not to practise law in the state of New York for two years. Williams & Connolly is based in Washington DC.

According to Cuomo's statement announcing the settlement, Aufhauser's trading occurred during the auction rate securities crisis. On 14 December 14, 2007, Aufhauser was on a train from New York to Washington DC, when he read an email sent that day by UBS's chief risk officer. The message described serious problems with UBS's auction rate securities market. A few minutes later, Aufhauser sent an email to his financial adviser and told him to sell all of his auction rate securities, according to the statement.

The District of Columbia Bar's Web site shows no disciplinary actions taken against Aufhauser. He is not a member of the New York Bar.

Last November Raoul Weil, the chairman and CEO of the global wealth management and business banking division at UBS, was indicted by a federal grand jury on charges that he helped US taxpayers avoid income taxes on assets in overseas accounts.

Sign up to receive In-house News Briefing, Legal Week's new digital newsletter

Click here to join Legal Week's LinkedIn In-house lawyers group