Coal companies have been continually citing one data point they believe will lead to a turnaround in the coal markets: Inventories at power generation facilities are at historical lows and, today, are equivalent to less than two months' worth of supply. As promising as this may sound for coal producers like Peabody Energy (BTU) and Arch Coal (NYSE: ACI), they seem to be missing one aspect of this data: These historical lows are by design.

With natural gas production continuing to soar, utility companies like Southern (SO 1.15%) are deliberately not buying coal or natural gas on long-term contracts because they want to get the best price, so there has been a major uptick in total coal purchased on the spot market over the past year. Find out why this may continue to keep overall coal volumes down over the next couple years, and why Peabody, Arch, and Alpha Natural Resources (NYSE: ANR) have much more to deal with than just sale volumes, by tuning into the video below.