Exxon Mobil Corp., the world’s biggest energy company by market value, is weighing a sale of its German Esso gas station chain, according to people familiar with the process.

The unit, which includes more than 1,100 gas stations in Germany, may fetch more than 1 billion euros ($1.3 billion), said two of the people, who asked not to be identified because talks are private. Exxon is in preliminary talks with multiple parties, two or three of which may be from Russia or eastern Europe, people said. No final decision on a sale has been made.

Exxon CEO Rex Tillerson has divested almost one-third of the company’s filling stations during the past four years to exit markets where fuel demand is stagnating or declining, and has focused investment on higher-profit oil wells and chemical production. Exxon’s portfolio of owned or leased filling stations fell to 7,753 as of Dec. 31 from 11,446 at the end of 2007, according to a company statement.

In 2010, Exxon Mobil agreed to sell its downstream activities in Austria to Eni SpA, Italy’s largest oil producer, which gained a retail network with 135 service stations. In March last year, the U.S. company agreed to sell Argentine assets including a refinery and gas stations to Bridas Corp., the oil company part-owned by China National Offshore Oil Corp.

Exxon’s profit margin from refining and selling motor fuels was 1.3 percent in 2011, compared with a 74 percent margin from pumping oil and natural gas, and 10 percent from its chemical business, according to company reports.

Exxon Mobil Central Europe Holding GmbH, the Hamburg-based holding company that includes the German business, had 2011 sales of 12.8 billion euros and operating profit before taxes and interest of 856 million euros, according to its website. The business includes oil, natural gas and refineries as well as 1,103 gas stations, according to the website.

An Exxon Mobil Central Europe spokeswoman, Gabriele Radke, declined to comment on any possible process.