National Bank Financial cautions that Canadian stock prices may be getting ahead of themselves.

In a research note, NBF observes that the S&P/TSX continues to ride the commodity bull market, reaching another record high close on Thursday. “Compared to other benchmarks all over the world, the Canadian index is clearly going it alone,” NBF says. “It’s the only major index that has bounced back to its July 19 pre-credit crunch peak.”

Even compared to other commodity-heavy country indexes, the S&P/TSX is still in a class of its own, NBF says. It reports that Australia and the U.K. have around 35% of their weighting in energy and materials, but their indexes are down 7.7% and 6.3%, respectively, from their July 19 level. “Even the Norwegian index which has a 66.4% weight in resources (more than Canada at 49.4%) is still 3% lower over the same period,” it notes. “In our opinion, the S&P/TSX might be ahead of its fundamentals,” it says. It reports that, according to the OECD, global leading indicators are pointing to slower growth in the months ahead, a development normally consistent with softer commodity prices.

Indeed, NBF says that according to data released Wednesday by the OECD, the composite leading index of industrialized economies fell for the ninth consecutive month in March. “On a six-month annualized basis — the preferred measure to gauge momentum — the index is now down 2%, the worst showing since 2001,” it reports.

“Looking back at the past decade, we found that commodity prices normally correct between 10% and 20% over a period of six months after the global CLI drops well below 2%,” it points out. “Even, on a technical basis, the Canadian benchmark might be a little stretched,” NBF adds, suggesting that the S&P/TSX is now in overbought territory.

“The recent rally might run out of fuel as we see few catalysts both in fundamental and technical terms,” it concludes.