Toyota Motor and Mazda Motor are closing in on a capital partnership deal to pave the way for possible establishment of a joint-venture U.S. auto plant and joint development of key electric vehicle technologies, The Nikkei learned Thursday.

The two Japanese automakers are negotiating on the premise that Toyota will take a roughly 5% stake in Mazda, which in turn would invest in the other party as well. They will announce the tie-up as soon as Friday.

The deal would further the consolidation of the global auto industry around the four leading camps, centering on Toyota, Germany's Volkswagen, America's General Motors and the alliance between France's Renault and Nissan Motor.

The U.S. is a revenue pillar for both Toyota and Mazda, and they will discuss building a plant together in the American South via a joint venture. The leading plan envisions a major factory with annual output capacity of up to around 300,000 vehicles, primarily sport utility vehicles, which enjoy high popularity in the U.S. Each automaker would sell the cars they make at the plant through their own channels. Building it jointly would reduce each party's investment burden and let them pool their expertise in specific production technologies.

The two companies face a growing risk of protectionist trade policies in the U.S. under the Donald Trump administration. Just around half the cars Toyota sells in the U.S. are made locally. Mazda lacks a factory there and imports vehicles from countries such as Mexico and Japan. A joint factory could soften American wariness toward the growing market share held by Japanese cars.