Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of Freeport-McMoRan Inc (NYSE:FCX) are freefalling today, down 12% as of this writing as worries about global economic growth rock the commodities market once again.

So what: The main reason the stock is down today is because the price of copper has plunged 5% to $2.512 per pound, lower than we've seen since mid-2009. This is a big deal for Freeport-McMoRan: copper is more than half of the company's business, and it expected to sell 3.9 billion pounds of copper in 2014. For perspective, through the third quarter it had a production cost of $1.92 per pound, not including overhead.  

Between the average realized price in the first nine months of 2014 of $3.14 per pound and today's price of $2.51 per pound, Freeport-McMoRan could potentially lose $2.46 billion in revenue this year (assuming 2015 production is flat). Unless the market turns around, that could be enough to wipe out nearly all of the company's potential profits for the year.  

Now what: Nothing seems to be going Freeport-McMoRan's way these days. Copper prices are plunging, gold is in a multi-year decline, and oil is off over 50% from 2014 highs. Given the commodity pressure, it's no surprise that shares are hitting a 52-week low today. If commodities stay where they are it's possible Freeport-McMoRan's un-hedged operations will run at a loss this year, a shocking reversal given the fact that analysts expect a $2.10 profit per share for 2014.