Naturgy, one of Spain’s major natural gas buyers, said last week it has negotiated new terms for two contracts with one of its primary LNG suppliers in a dual symbol of how the global gas trade is evolving and how such discussions can have varying outcomes.

A supply glut and weak market made weaker by the Covid-19 pandemic, along with a spike in spot trading of cheap LNG as prices have fallen precipitously, have given major buyers from Petronet Ltd. to China Petroleum & Chemical Corp., aka Sinopec, an opening to pursue better deals and review supply contracts over the last year or so. But that’s not necessarily an easy thing to do. 

Naturgy released few specifics and said only in a regulatory filing that its annual contracted volume was reduced and the price formula was...