While poor performance in stocks typically sends investors looking for returns in commodities, that's not been the case for the last several weeks; in many cases, the best-performing resources are seriously underperforming stocks. For metal mining giant BHP Billiton ( BHP), that's been precisely the case. While this stock had been forming an ostensibly bullish setup for the last several months, a breakdown sends a very different signal right now. Since the beginning of November, shares of BHP Billiton had been forming an ascending triangle, a pattern that's normally thought of as a bullish formation. But just last week, shares broke below the pattern's uptrending support line, a signal that the pattern no longer held water. A breakout to the downside is more than just a "no go" signal, however -- particularly in a lower market. A downward breakout from a descending triangle signals a strong shorting opportunity for the stock, one that's actually statistically more effective than the traditional upward breakout that would have bulls interested. If you're interested in a short play on BHP, I'd suggest placing your protective stop just above the trend line at around $78. As of the most-recent period, BHP showed up in the portfolio of Ken Fisher's Fisher Asset Management, comprising 1.6% of the total portfolio. It also showed up on a recent list of the 20 top-yielding metals and mining stocks.