JPMorgan Chase quintupled its original bid for Bear Stearns to $10 a share on Monday after its initial offer for the beleaguered Wall Street bank was undone by legal snags and furious opposition from Bear shareholders who viewed it as far too low.

The new all-share offer, coupled with surprisingly strong home sales data, helped spark a broad market rally in the US when investors hoped the worst fallout from the subprime mortgage crisis might be at an end. All three big US stock market indices were up at least 2 per cent in midday trade.