GENEVA — BMW could decide as early as this summer whether to begin sourcing transmissions in the U.S. for its manufacturing plant in Spartanburg, S.C., the group's largest in the world.

Transmissions are a high-value and complex piece of automotive hardware that import brands often source from trusted suppliers in their home markets. But a further localization of key powertrain components could act as an insurance policy against possible U.S. tariffs, should the Trump administration act on the president's threat to impose duties on imported vehicles and parts.

More practically, resourcing transmissions to the U.S. also would serve BMW as a hedge against currency fluctuation, a critical issue in international supply chains.