(Adds details, comments, official closing data)
By Wojtek Dabrowski
TORONTO, March 31 (Reuters) - The Toronto Stock Exchange's main index finished Monday's scattershot session in positive territory after a series of wild swings that saw the benchmark jump, plunge and surge again as volatility ruled.
The key S&P/TSX composite index .GSPTSE rose 116.34 points, or 0.88 percent, to close at 13,350.13. Earlier, the index set the day's low at 13,131.08.
"I think what investors are trying to do is they're trying to see some daylight," said Adrian Mastracci, portfolio manager at KCM Wealth Management Inc, in Vancouver, British Columbia. "They're not really finding it yet."
All but one of the 10 main index groups ended higher, including the key energy and financials groups, which added 0.68 percent and 3.34 percent respectively.
The materials group was the sole decliner, shedding 1.67 percent.
The see-saw session began with a rise of more than 100 points, but by 3 p.m., the index had plunged by the same amount. The last hour saw another change in direction, leading to the positive finish.
There was relatively little corporate news or other data to sway investor sentiment on Monday aside from U.S. Treasury Secretary Henry Paulson's proposed overhaul of that country's financial regulatory landscape.
That could have helped steady some nerves and helped the rally in financial shares, said Ian Nakamoto, director of research at MacDougall, MacDougall & MacTier.
As well, the session is the last of the quarter, and fund managers often tweak the contents of their portfolios ahead of a quarter's end in a practice sometimes referred to as "window-dressing", Mastracci said.
$1=$1.03 Canadian Reporting by Wojtek Dabrowski; Editing by Peter Galloway