Citizens Financial Group, the US unit of Britain's Royal Bank of Scotland, said its initial public offering was expected to raise as much as $3.5 billion, making it the biggest US offering by a bank this year.

The company said the offering of 140 million shares was expected to be priced at between $23 and $25 each. At the top end of the range, the company would be valued at $14 billion.

All the shares in the offering are being sold by RBS.

RBS said last year it would sell 20-25 per cent of Citizens by the end of 2014 through a US IPO as the bank faces pressure from British regulators to bolster its capital and sell off non-core assets.

Citizens had $130.3 billion of total assets and more than 1,200 branches in 11 states across the New England, Mid-Atlantic and Midwest regions as of June 30. – (Reuters)