Under their new rules, global taxation authorities have been discussing a proposal of targeting digital giants and other multinationals whose profit margins top 10 percent, Japanese government sources said Saturday.

The debate on creating global tax rules based more on where firms make their sales rather than on where their permanent offices are located has been growing at the Organization for Economic Cooperation and Development and international forums such as the Group of 20 (G20).

A working group of the OECD is likely to outline the draft rules next month, the sources said.