TORONTO (Reuters) - The Toronto Stock Exchange's main index rose on Wednesday, snapping a nearly 4 percent percent rout in the previous session, led by strength in the energy sector as oil stabilized following a surprise decision by OPEC to cut production.

Shortly after the open, the S&P/TSX composite index <.GSPTSE> was up 272.03 points, or 2.2 percent, at 12,418.79, with all 10 of its main groups higher.

The heavyweight energy sector led the rise, up 3.6 percent, as the price of crude stabilized following a surprise decision by the Organization of the Petroleum Exporting Countries to cut production by half a million barrels a day. Canadian Natural Resources <CNQ.TO> jumped 4.4 percent to C$77.64.

The resource-laden materials group was up 2.5 percent, despite softness in the price of bullion and as base metals fell, as investors snapped up stocks at bargain basement prices. Barrick Gold <ABX.TO> climbed 2.9 percent to C$28.82.

The rally comes after the benchmark index slipped 487.88 points, or 3.9 percent, on Tuesday on a commodities sell-off triggered by a tumble in oil.

Based on Tuesday's close, the benchmark index had posted triple-digit losses in five of six sessions, shedding more than 11 percent in a week. This pushed it to within striking distance of a bear market, which is defined as a 20 percent decline from its peak.

($1=$1.07 Canadian)

(Reporting by Jennifer Kwan; Editing by Scott Anderson)