Sydney, Nov. 16 (Reuters): Rio Tinto is reportedly considering a counterbid for BHP Billiton as a defence against an A$140-billion takeover proposal from its bigger mining rival, but analysts said such a move was unlikely.

The Wall Street Journal, citing unnamed sources, reported Rio was considering a broad array of options to fight off BHP, including a so-called Pac-Man defence, selling assets and other moves that could raise shareholder value.

The term Pac-Man defence is a reference to a computer game popular in the 1980s where attackers can become the attacked.

BHP shares in London jumped as much as 2.4 per cent on the speculation that it might become a target and were trading 1.3 per cent higher at 1,618 pence by 0955 GMT.

Rio shares ticked 0.24 per cent higher to 5,433 pence, outperforming a 0.5 per cent fall in the UK mining index.

However, analysts said Rio was unlikely to counter-bid as expectations are growing that BHP may sweeten its offer, and it may be difficult anyway for the smaller Rio to pull off such a move.

“At face value you’d say it’s unlikely and high risk,” said Peter Chilton, investment analyst at Constellation Capital Management, one of several Sydney-based fund managers BHP chief Marius Kloppers tried to persuade this week to back his idea of a mega miner, controlling much of the world’s supply of raw materials.

Investor meet

Rio had already planned a general investor briefing for November 26 before BHP announced its planned bid last week and will use the opportunity to give its perspective on the situation, Rio spokesman Nick Cobban in London said.

Neither Rio nor BHP would comment on the newspaper report.

Earlier this month, Rio Tinto said BHP’s three-shares-for-one takeover proposal “significantly undervalues Rio Tinto and its prospects.”

“I would be very, very surprised if it happened,” analyst Tom Gidley-Kitchin at Charles Stanley said in London.