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 silica producer U.S. Silica (NYSE: SLCA) rose more than 10% today after the company was upgraded by an analyst.

So what: BB&T was the culprit today, initiating coverage on the stock with a buy rating. The company gave the stock a $17 price target, nearly a 50% increase from the current stock price.

Now what: We don't put a lot of stock in analyst ratings at The Motley Fool, and I wouldn't buy today just based on this buy rating. The stock's more important move was after the company released earnings two weeks ago that topped estimates. Shares are now trading at just six times forward earnings, and I think that will be the driver of the stock going forward, not how an analyst is rating the stock.

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