HOUSTON — Citgo has long been a mainstay of the American oil industry, with three major refineries, 4,500 gasoline stations and an iconic sign looming over Fenway Park’s left field wall.

Now, the company could be splintered into pieces, a casualty of the turmoil in Venezuela.

As the American subsidiary of the Venezuelan national oil company, Citgo is the object of international political scheming, legal maneuvering and financial gamesmanship. Unless Venezuela’s national oil company makes a $913 million payment on its 2020 bonds that is due Oct. 28, creditors and other businesses that have claims against Venezuela’s socialist government could try to seize Citgo.

“Everyone wants the Citgo assets because it’s the only way to get paid,” said Francisco Monaldi, a fellow in Latin American energy policy at Rice University.

The situation has pitted various groups against one another and set off a flurry of negotiations. Bondholders want assurance that they will be repaid. Citgo and Juan Guaidó, the opposition leader whom the United States, the European Union and other governments consider Venezuela’s legitimate head of state, want to avert a breakup of the company, and they are urging the Trump administration to act on their behalf.