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 RadioShack (NASDAQOTH:RSHCQ) were getting tuned out again today, falling as much as 13% after Standard & Poor's downgraded the company's debt rating.

So what: The S&P dropped the struggling electronics retailer to CCC, or eight degrees below investment-grade, and warned that RadioShack could default within a year if things don't turn around. The downgrade comes off RadioShack's earnings report last week, which showed a larger loss than expected as the shortfall hit $0.53 a share. Analysts had expected a per-share loss of just $0.24.

Now what: The company has been attempting to cut costs and restructure, focusing on wireless phone sales for one, but with revenue tumbling and the losses mounting, the turnaround will be tough to pull off. As of June 30, cash on hand and receivables was only $23,000 more than its current liabilities, meaning the company is nearly underwater. A spokeswoman noted that RadioShack retired $216 million in debt yesterday with cash on hand, which may stave off liquidity concerns for now, but if the company can't improve its cash position, the stock will continue to fall.