Citigroup's boss Charles Prince led the improvement to its practices

The bank was hit with the order in March last year. Although authorities did not accuse Citigroup of wrongdoing, it was told to improve its practices.

In a letter to the firm, the Federal Reserve Bank of New York said Citigroup had since made "significant progress".

Citigroup has seen a number of scandals in recent years.

In 2004 its Japanese private bank was shut by Japan's financial regulators, and it has also been criticised for selling bonds too quickly.

'Shared responsibilities'

Citigroup's response to the order against pursuing big takeovers came in the form of a five-step plan to address compliance issues, led by its chief executive Charles Prince.

In a memo to Citigroup staff reported by the AP news agency, Mr Prince said he was "very pleased" by the Federal Reserve Bank of New York's ruling.

"We dedicated ourselves to our shared responsibilities to our clients, to each other and to our great franchise, and we strengthened our controls, compliance and culture through the five point plan, which we continue to implement," he said.

The announcement by US federal authorities comes just four days after Citigroup was sued for insider trading by Australia's securities regulator.