Some natural gas prices at trading hubs in the Appalachian Basin's Marcellus Shale play are trading well below the national benchmark spot price at the Henry Hub in Louisiana. Over the past month, spot prices at many Appalachian hubs have dropped below $2 per million British thermal units (MMBtu) on days of low demand, while spot prices at Henry Hub and throughout much of the United States have traded near $4/MMBtu.