Daihatsu, Isuzu, Mazda, Subaru and Suzuki are the latest Japanese automakers to join Monet, a firm led by Toyota and Softbank, and with significant investments from Honda and Hino.
The company's first goal is to roll out on-demand car services, and by 2023 it hopes to have self-driving vehicles based on Toyota's e-Palette concepts (above).
Softbank is the largest investor having put just over ¥1 billion ($13.4 million) into the firm and controlling 35.2 per cent. Toyota owns 34.8 per cent of Monet.
This latest round of investment seemingly pulls Mazda, Subaru and Suzuki closer into Toyota's orbit.
Mazda already has a number of joint projects with Toyota, including rebadging the Mazda 2 as the North American Toyota Yaris, and is rumoured to be developing a rear-wheel drive platform to be shared with the larger automaker.
Suzuki and Toyota have recently entered an alliance, where Suzuki will gain access to Toyota's hybrid technology and will rebadge a number of Toyota models for sale in Europe. In return Toyota will lightly makeover some Suzuki vehicles for the Indian and African markets.