The investments, announced during a visit to Seoul by President Joe Biden, are for robotics, urban air mobility, autonomous driving and artificial intelligence, the group said.
Hyundai Motor Group, which houses Hyundai Motor Co and Kia Corp, on Friday announced plans to invest $5.5 billion in Georgia to build electric vehicle (EV) and battery facilities.
Hyundai's new EV and battery manufacturing facilities will be based in the southern "right to work" state, where labour unions are less prevalent and cannot require workers to join.
Biden, a Democrat, has described himself as the most pro-union president in history. But the deal, announced by Georgia's Republican governor, showed the compromises the president may have to make as he woos investment overseas.
"Hyundai and any company investing in the United States would benefit greatly from entering into partnerships with some of the most highly skilled, dedicated, and engaged workers in the world, anywhere you can find; and that is American union members," Biden said.
"Every venture to manufacture electric vehicles and electric vehicle batteries would be made stronger by a collective bargaining relationship with our unions."
Hyundai Motor Group Executive Chair Euisun Chung did not comment on U.S. unions.
The new investment brings its planned U.S. total through 2025 to about $10 billion, above the $7.4 billion it announced last year.
The world's third-biggest automaker by vehicles sales did not say where in the United States the additional $5 billion would be invested.
The auto group said on Wednesday it would invest 21 trillion won ($16 billion) through 2030 to expand its EV business in South Korea.
($1 = 1,273.5900 won)
Hyundai Motor Group to invest $5.5 bln to build EV and battery facilities in U.S.
(Reporting by Trevor Hunnicutt, Heekyong Yang and Jack Kim; Editing by Bradley Perrett and Lisa Shumaker)
By Trevor Hunnicutt and Heekyong Yang