What happened

Shares of coal miner Peabody Energy (BTU -1.25%) are down heavily in Tuesday morning trading, falling 12.2% through 10:40 a.m. EDT on no apparent news at all.

So what

Crazily, if there is news today, it's news that would seem to be good for Peabody. Specifically, coal prices that have been climbing since April (up 67%) spiked particularly sharply over the weekend, rising 9% in Monday trading.  

Seeing Peabody stock fall on that news is kind of weird. Then again, it's also kind of par for the course, because after topping out at $4.07 midmonth, Peabody shares have been on a more or less uninterrupted slide ever since, losing about one-third of their value even as coal prices got better and better.  

Commodity sector trading screen shows Coal with a red down arrow

Image source: Getty Images.

Now what

So why is Peabody stock reacting contradictorily to how we'd expect? Really, only two theories suggest themselves. First, coal is a cyclical commodity industry. If prices are rising so steeply now, investors may be peering into the future and assuming that this is as good as it gets, and prices are certain to fall sooner or later.

Second -- perhaps related to the first -- you may not have heard, but there's a presidential election underway, and right now Democrat Joe Biden is leading in the polls. If the pro-coal President Trump gets voted out of office in November, investors may be assuming that this will be bad news for coal, for coal prices, and for coal stocks like Peabody.

Today, we may simply be seeing investors getting while the getting is good.