We're seeing a very similar setup in shares of BHP Billiton PLC ( BBL) right now. That's not hugely surprising -- BBL and COP are two large-cap commodity-driven stocks, so their price charts are all but guaranteed to correlate highly with one another. Just like with COP, we'll want to see a bounce off support for the buy signal to trigger in BBL. >>4 Big Stocks to Buy in February -- and One to Sell More recently, the 50-day moving average has acted as a good proxy for trend line support. That simplifies things for traders looking to enter this stock on a bounce; setting a trade alert (through your broker) when shares close below the 50-day will provide an early warning that this setup is failing. I'd recommend keeping a protective stop just below that level.