Nissan Motor Co. and Renault SA said Monday they have formally agreed to make their mutual cross-shareholdings equal at 15 percent, in a deal that will radically change the decades-old capital alliance that created one of the world's biggest automaker groups.

Under the agreement, the French company will reduce its 43.4 percent stake in the Japanese automaker while Nissan will maintain its current stake in its alliance partner.

While Renault will allow Nissan more autonomy, the Japanese company will, in turn, hold an up to 15 percent stake in Ampere, a new electric vehicle company to be set up by the French carmaker. Another alliance partner, Mitsubishi Motors Corp., will also consider investing in the new company.

"We can no longer stay still or work as an extension of the past," said Nissan CEO Makoto Uchida at a press conference held in London. "We need to have the next level of transformation."

Renault CEO Luca de Meo said, "We can preserve the scale, all of us" in the alliance. He added that the renewed alliance also allows each company to operate uniquely.

Renault will retain 15 percent of the 43.4 percent share in Nissan and transfer the remaining 28.4 percent to a French trust. Renault is in no hurry to sell its holdings, de Meo said.

The capital alliance dates back to 1999 when Renault became the top shareholder in Nissan, which was then on the cusp of bankruptcy. Carlos Ghosn was sent from Renault to lead the overhaul.

But as Nissan recovered from the crisis, its officials have come to see the relationship as unequal, given it has larger vehicle sales than its French partner, as well as a technological lead in EVs, which led to a growing opinion that the current alliance should be reviewed.

Renault, for its part, was in need of cash to strengthen its EV business, especially after it was forced to pull out of the Russian market following the war in Ukraine.

Mitsubishi Motors joined the alliance after Nissan acquired a 34 percent stake in it in 2016.

Related coverage:

Nissan, Renault agree to make mutual cross-shareholding equal