The justices left in place a 2015 ruling by the 2nd US Circuit Court of Appeals in New York that favored the two companies. That court decided that the plaintiffs failed to show that there was a close connection between decisions made or actions taken by Ford and IBM in the United States to killings, torture and other human rights abuses that took place in South Africa from the 1970s to early 1990s.
Ford was accused of providing military vehicles for South African security forces and sharing information about anti-apartheid and union activists. IBM was accused of providing technology and training to perpetuate racial separation and the "denationalization" of black South Africans.
Apartheid refers to South Africa's former white-minority government's policy of segregating and oppressing the majority black population from 1948 to 1994.
The plaintiffs, led by Lungisile Ntsebeza, sued more than a decade ago under the Alien Tort Statute, a 1789 US law that lets non-US citizens seek damages in American courts for human rights abuses abroad.
But the US Supreme Court significantly narrowed the reach of that law in 2013, leading US District Judge Shira Scheindlin in 2014 to dismiss the South African plaintiffs' case.
Germany's Daimler AG and Rheinmetall AG were dismissed as defendants in the case in 2013. Dozens of other companies were previously dismissed.
Apartheid ended in 1994 when South Africa held its first all-race elections, bringing Nelson Mandela and the African National Congress to power.
© Thomson Reuters 2016