The cost to transport a shipment of U.S. liquefied natural gas to energy-starved Europe turned negative, a dramatic reversal that illustrates a growing glut of ships in the Atlantic ferrying American fuel.

Spot freight rates in the Atlantic crashed to -$750 per day on Tuesday, down from $273,000 in early December, according to Spark Commodities, which tracks LNG shipping prices. That’s the first time the marker has turned negative in Spark data going back to 2019, and means that — at least theoretically — owners are paying charterers to use their ships.