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 Permian Basin Royalty Trust (NYSE: PBT) sank as low as 11% in intraday trading Tuesday on substantially higher than average volume.

So what: At the time of publication, more than 1 million Permian Basin shares had already changed hands, versus the three-month average volume of just 175,000 shares. The stock hit a daily low of about $19.40 just after 11 a.m., but has since recovered a good chunk of that loss and sits at about $20.60 -- down about 6% for the day.

Now what: Mr. Market might be providing Fools with a juicy income opportunity. Without any big news coming out of Permian Basin, I'm taking today's crazy action as part of the usual volatility that goes with being so levered to energy prices. Rivals Hugoton Royalty Trust (NYSE: HGT) and Sabine Royalty Trust (NYSE: SBR) are also off more than 3% today, so investors would do well to keep today's loss in perspective.

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