TORONTO (Reuters) - Surging commodity prices propelled gold and energy shares to a big win over weak financials on the Toronto Stock Exchange yesterday, as the volatile session ended with a gain of more than 5.5 percent.

Every one of the 10 main subgroups of the S&P/TSX composite index rose by the end of the day, despite earlier volatility that saw the benchmark wheeling wildly between positive and negative territory.

The composite closed up 430.63 points, or 5.57 percent, at 8,155.39. Earlier in the day, the benchmark hit a low of 7647.11.

But even with yesterday's broad rally, the TSX was still down 9.9 percent for the week.

Energy issues and the resource-heavy materials group rose 9.9 percent and 19 percent, respectively.

Gold surged more than five percent as investors once again flocked to the asset as a safe-haven during a recession. Oil rose one percent as stock markets recovered, also receiving a boost from a weaker US dollar.

It was little surprise, then, that gold and oil companies figured prominently among the day's biggest net gainers. Barrick Gold rose 32.5 percent to close at C$35.50. Agnico-Eagle Mines surged 21.2 percent to C$41.80.

In the oil patch, EnCana Corp. shot up 10.9 percent to end at C$48.66. Petrobank Energy rose 24.3 percent to C$21.75.

Financials, which were battered lower almost all day, recovered to finish 0.34 percent higher.

Investors in Canada and the US kept a close eye on the plummeting shares of Citigroup throughout the session, as speculation swirled the banking giant may sell major businesses to shore up its health.

"When Citigroup is getting hit like this, I mean it's just unbelievable," said Sal Masionis, a stockbroker at Brant Securities, adding that Canadian banks were also suffering as a result. "It's just brutal."

Toronto-Dominion Bank fell 5.2 percent to end at C$41.30.

Citigroup is also one of the banks underwriting the C$34.8 billion buyout of Canadian telecom giant BCE Inc. Worries about the bank's health dragged on BCE shares Friday, sinking the stock 2.7 percent to C$34.55 - well below the buyout price of C$42.75 a share.

Reports that US President-elect Barack Obama had chosen Federal Reserve Bank of New York head Timothy Geithner to be his treasury secretary also buoyed investor sentiment late in the trading day.