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 wire-maker General Cable (NYSE: BGC) plummeted 19% on Tuesday after its quarterly results and outlook missed Wall Street expectations.

So what: General Cable's third-quarter results -- earnings plunged to $0.07 per share from $0.34 in the year-ago period -- indicate just how susceptible it is to highly fickle metal prices, currency shifts, and global demand. On an ugly market day like today, when fears over the world economy are running rampant, General Cable's volatile business model isn't exactly what investors want to be exposed to.

Now what: Looking ahead to the fourth quarter, management sees revenue of just $1.40 billion to $1.45 billion, while analysts were expecting $1.56 billion. In fact, CEO Gregory Kenny said that the quarter will be "burdened by the impact of selling higher average cost inventory into a lower and volatile metal price environment." General Cable's short-term prospects certainly aren't rosy, but with the stock flirting with 52-week lows and trading at a forward P/E of roughly six, much of the risk might already be baked in.

Interested in more info on General Cable? Add it to your watchlist.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.