Hartford shares plunge 52 pct after massive loss

* Hartford shares hit all-time low, close at $9.62

* Cost of insuring Hartford debt rises

* Prudential stock drops 18 percent

(Recasts, adds new information on costs to insure Hartford debt, updates share prices)

By Lilla Zuill

NEW YORK (Reuters) - Shares of Hartford Financial Services Group Inc (HIG.N) plunged nearly 52 percent on Thursday, a day after the property and life insurer posted a much larger than expected quarterly loss, stoking concerns it may need to raise even more capital to survive.

The share decline brought Hartford's market value down to $2.9 billion, not much more than the $2.5 billion that German insurer Allianz SE (ALVG.DE) agreed to inject into the company earlier this month.

Chief Executive Ramani Ayer told investors late Wednesday that the third quarter was the worst in the insurer's 198-year-old history. Hartford lost money mainly from bad investments in financial companies.

"I honestly missed the degree to which markets have cratered," Ayer said late Wednesday.