Trouble is brewing on the European gas market. In the wake of a long, cold winter, natural gas reservoirs are unusually low and should, in principle, be refilled very quickly. Russia’s state-owned corporation Gazprom could increase supplies. The market leader, however, has not done that, despite prices recently reaching a 13-year high. In turn, there is growing concern across Europe that there may be insufficient gas supplies for the upcoming winter. Gazprom has not booked any additional gas transit through Ukraine in July, although deliveries of Russian natural gas to the EU will drop by more than 2 billion cubic...