What: Shares of Cliffs Natural Resources Inc (CLF 0.95%) are up more than 27% today in anticipation of the company's earnings report tomorrow.

So what: This is speculation at its best in Cliffs Natural Resources. A day ahead of earnings, investors are bidding up the stock hoping the company beats earnings. The market rumor today is that the company will report a loss of $0.09 per share instead of the expected loss of $0.11 predicted by Wall Street analysts. Zacks has helped drive this narrative, saying that the "Most Accurate Estimate" for the quarter is a $0.09-per-share loss.

Now what: Iron ore and metallurgical coal have been crushed on the market, and a potential slowdown in the Chinese economy could make the commodity problems worse. Even the optimistic speculation on Cliffs Natural Resources today is that it will lose money, which is terrible for a company with nearly $3 billion in debt. I would stay away from this rumor-driven stock today; I don't see the pop or the company's operations as sustainable over the long term.