* Toronto index unravels nearly all of Wednesday’s gain
* Banks and energy shares lead index’s triple-digit skid
* Economic concerns hover over index
By Frank Pingue
TORONTO, Jan 29 (Reuters) - Toronto’s key stock index ended lower on Thursday as nagging economic concerns hurt weighty bank shares and lower oil prices hit the energy group, forcing the TSX to undo nearly all its gains from the prior session.
Data from the United States that supported the notion of a deepening economic slump clouded an already dark outlook for bank and insurance companies and knocked the financial sector down 4.28 percent.
Lower prices for oil, a key Canadian export, coupled with news that Petro-Canada PCA.TO swung to a quarterly loss, were the main cause of the energy group’s 2.58 percent skid.
“This is the sort of common stuff and the way that markets are and this is what we’re going to have to deal with,” said Brian Pow, a research and equity analyst at Acumen Capital Partners in Calgary.
Among the key shares weighing on the index in the latest session were insurer Manulife Financial (MFC.TO), which fell 6 percent to C$20.57, and energy company EnCana Corp (ECA.TO), which dropped 3.55 percent to C$55.19.
The Toronto Stock Exchange’s S&P/TSX composite index .GSPTSE fell 143.47 points, or 1.61 percent, to 8,762.76, following a 146 point gain on Wednesday.
$1=$1.22 Canadian Editing by Jeffrey Hodgson