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 metals company Stillwater Mining (NYSE:SWC) fell as much as 12% today after announcing a debt offering.

So what: The company intends to offer $300 million in convertible notes due 2032 with a provision for over-allotment for underwriters, which could push the offering up to $345 million. The conversion rate for the stock is unknown, but there is a provision that says that, "If the price of the Company's common stock exceeds the base conversion price during specified periods applicable to conversion, holders will receive additional shares of the Company's common stock upon conversion." So, bondholders could get a large upside in the stock, diluting current shareholders.

Now what: We still don't know the conversion details, so it's hard to establish the exact dilution or the impact on shareholders, right now. As the company moves closer to the offering, and releases final details, investors should look at how it will impact the stock. The move lower today is speculation that upside in the stock will be diluted by bondholders, which is never something stock investors like to see.

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