Shares in Rupert Murdoch’s News Corporation have fallen as more allegations emerge in the phone hacking scandal engulfing its British newspaper empire.

The widening crisis has prompted Macquarie Bank analysts to slap an ‘‘underperform’’, or sell, rating on News Corp, warning the company faces regulatory risks in both the UK and US.

News Corp shares shed 73 cents, or 4.6 per cent, to close at $15.19, following a 5 per cent fall yesterday.

In a note to clients, Macquarie analyst Alex Pollak cut his valuation of News Corp by 18 per cent, ‘‘on the basis of high level regulatory uncertainty in the UK and US’’.

The company may face the risk of an investigation into whether it is a ‘‘fit and proper’’ person to hold US TV licenses, Mr Pollak said.