TORONTO (Bloomberg) — Canadian stocks had their biggest weekly gain in three months, on take-over speculation, after uranium explorer UraMin agreed to be bought by Areva SA, and Total SA was reported to be preparing a bid for Western Oil Sands.

Global demand for energy and metals have helped commodities rise to records amid a take-over boom, boosting Canada's main stock index, almost half of which is commodity-related, to a record earlier this month.

"There's a huge amount of M&A and there will be more of it, but it's unpredictable," said Rick Hutcheon, who manages about $171 million as chief investment officer at RKH Financial in Toronto. "We've got the reserves and we've been selling them. There's a lot of cash around. Why spend on exploration if you can buy them."

The Standard & Poor's/TSX Composite Index added 135.42, or one percent, to 14,137.41 in Toronto. The benchmark had a weekly gain of 2.5 percent, the best since a 3.2 percent rise in the week ended March 23. The index had dropped 2.3 percent the previous week on concerns that rising bond yields and interest rates would curb profit growth and acquisitions. The index is within 10 points of its June 4 record of 14,146.74.

Uramin advanced 91 cents, or 11 percent, to C$8.85 in Toronto. Areva, the world's largest manufacturer of nuclear plants, offered to buy UraMin, a uranium explorer in sub-Saharan Africa, for more than $2.5 billion, or $7.75 a share, in cash, Johannesburg-based UraMin said.

UraMin's board supports the bid. Uramin shares have more than doubled in 2007 after uranium prices appreciated more than sixfold in the past three years.