The Globe and Mail reports in its Friday edition that a curious rally took hold this week, led by the oil sands' two biggest names: Suncor and Canadian Natural Resources. The Globe's Tim Shufelf writes that their stocks rose by 37 per cent and 45 per cent, respectively, in just two trading days. Trading data show an enormous level of buying in those two stocks -- about $1-billion worth in two days -- rumoured to be on behalf of a single U.S. investor. In stock forums and on Twitter, speculation swirled that Warren Buffett was the man behind the big trade in the oil sands. The Berkshire Hathaway chief executive officer tends to be at his most aggressive in times of market distress, and is sitting on a mountainous cash hoard that totalled $128-billion (U.S.) as of the end of last year. Plus, the company already owns 15 million shares of Suncor. "Given the immense pressure on U.S. shale producers, investing in strong, well-financed energy firms like SU and CNQ would be a move consistent with Warren Buffett's style," Michael Sprung at Sprung Investment Management said of the two big producers. On the other hand, it is unusual to execute an order of that size all at once and send the stock price soaring as a result.