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 BP Prudhoe Bay Royalty Trust (NYSE: BPT) dropped as much as 16.5% in intraday trading Tuesday on extraordinarily high volume.

So what: At the time of publication, a whopping 1.5 million shares have already been traded, versus the three-month average of just more than 142,000 shares. The recent slide in oil prices has naturally weighed on the shares, as BPT investors have now experienced about a 25% drop over the past two weeks alone.

Now what: I wouldn't be so quick to pounce on BPT's recent weakness. BPT is still up roughly130% over the past year and, as my fellow Fool Dan Dzombak noted today, has been the top-performing dividend stock (among companies with market caps over $500 million) of the past millennium. BPT's dividend yield certainly looks juicy, but with that kind of spectacular price performance, more double-digit drops could be in the cards if oil continues to pull back.

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