The price of oil tumbled after Goldman Sachs cut its 2015 oil price forecasts and said rising output will outstrip demand.

The decline in the price of U.S. crude oil , which has slumped 21 percent in the last three months, has hit energy shares hard. The group has shed about 25 percent since the middle of June, weighing on the broader market.

The TSX’s decline on Monday follows the benchmark’s biggest weekly jump in more than a year. Fund managers said there could be more volatility in the coming months.

Investors are also expecting the Federal Reserve to provide further clarity about its monetary policy at a meeting this week. The U.S. central bank is seen assuring the markets that it is prepared to wait a long time before raising interest rates. [ID:nL2N0SH35O]

“I don’t think the Fed plans to give a major shock. I don’t see them looking for big changes,” said Adrian Mastracci, portfolio manager at KCM Wealth Management.

“They really want to stay out of the way as much as they can, but they want to give an impression that if they are needed they are ready to step back in,” he added.

The Toronto Stock Exchange's S&P/TSX composite index <.GSPTSE> closed down 74.82 points, or 0.51 percent, at 14,469. Five of the 10 main sectors on the index were in the red.

Shares of energy producers fell 2.8 percent. Canadian Natural Resources Ltd (>> Canadian Natural Resources Limited) lost 2.5 percent to C$37.95, and Suncor Energy Inc (>> Suncor Energy Inc.) gave back 1.9 percent to C$38.15.

The gold-mining sector was down 1.5 percent. Barrick Gold Corp (>> Barrick Gold Corp.) shed 1.5 percent to C$14.96, and Goldcorp Inc (>> Goldcorp Inc.) declined 1.2 percent to C$24.72.

(Editing by James Dalgleish and Cynthia Osterman)

By John Tilak