The tech firm will lead a consortium back by some of the world’s biggest banks, City sources told the Sunday Times.
Entering the global finance industry is seen as a key strategic objective of many of the world’s technology giants.
Under the plan, Softbank could acquire a large financial software business as a springboard to rolling out the new system.
Softbank is rumoured to have been circling Swiss firm Temenos, a firm that provides software to the majority of the world’s top financial institutions. Shares in Temenos jumped 20 per cent amid reports, which were later denied.
But market sources were reported as saying another mammoth deal was in Softbank’s pipeline.