Grab, the leading on-demand transportation and mobile payments platform in Southeast Asia, announced on Monday that China's Didi Chuxing and Japan's SoftBank Group Corp will invest up to 2 billion U.S. dollars to lead Grab's current financing round.

Grab anticipates that it will raise an additional 500 million dollars, bringing the total to 2.5 billion dollars in this round from existing and new investors.

This is the largest single financing in the history of Southeast Asia, Grab said in its press release.

According to Grab, DiDi and SoftBank will continue to support Grab's vision of helping consumers in Southeast Asia access safe transportation and financial products whilst creating employment opportunities.

Grab said it is by far the most dominant on-demand transportation platform in the region with a market share of 95 percent in third-party taxi-hailing and 71 percent in private vehicle hailing.

The company said it will continue to strengthen its already-leading market position and invest in GrabPay, its proprietary mobile payments solution.

Anthony Tan, Grab's Group CEO and Co-founder, said with the support of Didi and SoftBank, Grab will achieve an unassailable market lead in ridesharing, and build on this to make GrabPay the payment solution of choice for Southeast Asia.

Tan's counterpart in Didi, Cheng Wei, said by deepening strategic partnership, DiDi and Grab reaffirm their shared commitment to innovating localized solutions to global urban development challenges from the world's fastest growing marketplaces.

Masayoshi Son, Chairman and CEO of SoftBank, said Grab is believed to be a tremendously exciting company in a dynamic and promising region, and SoftBank is excited to deepen this partnership and looking forward to continuing to support Grab's journey.