Earlier reports said the Leafield based team had received a letter from Magma, headed by Martin Leach, explaining that the expected backing - thought to originate from Dubai - had been held up.
It is believed that the news could affect the team's ability to race in Spain next weekend without the intervention of Honda or Bernie Ecclestone.
Super Aguri confirmed on Wednesday that Magma's unnamed investors "no longer wish to fund the intended acquisition".
"It is with deep regret that Aguri Suzuki is now forced to consider the future of the team, however negotiations with other parties continue," the statement also read.
A further statement is expected in due course. (GMM)