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 Koppers Holdings (NYSE: KOP) jumped 10% today after the firm was added to the SmallCap 600 index.

So what: Seems like a mundane announcement, but when a stock is added to an index, funds that follow that index buy shares in droves. As a result, more than three times the daily average volume of shares has traded hands with nearly an hour left in the trading day.

Now what: Being added to the SmallCap 600 index is fine, but it shouldn't really change your investment thesis. And when the new buyers leave the market and trading returns to normal, shares may sink back down to where they were yesterday. No reason to panic a trade today unless you're looking for an attractive price to cash out.

Interested in more info on Koppers Holdings? Add it to your watchlist.

Fool contributor Travis Hoium does not have a position in any company mentioned. You can follow Travis on Twitter at @FlushDrawFool, check out his personal stock holdings or follow his CAPS picks at TMFFlushDraw.

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