Tesla and TEI President Oliver Johnson did not respond to requests for comment.
The specialists use sand casting in a process called rapid prototyping to help validate Tesla's designs and engineering specifications for its giant molds quickly and cheaply.
According to all four sources, TEI began helping Tesla around 2017 to develop the Model Y and is considered in the industry to be one of the world's top sand casting specialists.
"TEI will remain its own business entity with GM as its parent company," GM said.
Reuters was unable to determine whether Tesla was one of the several companies that bid for TEI.
Persons:
Joe Biden, Jonathan Ernst, Tesla, TEI, Oliver Johnson, Ford F.N, Elon Musk, TEI's Johnson, James Womack, Womack, David Clarke
Organizations:
Motors, REUTERS, Equipment, General Motors, GM, Ford, Hyundai, Toyota, Chief, Tesla's, Celestiq, American Foundry Society, GM's Global Manufacturing, Reuters, SEAT, Tesla, Massachusetts Institute of Technology, Thomson
Locations:
Detroit , Michigan, U.S, , Texas, Britain, Germany, Japan, TEI, Livonia, Detroit