The PMO had in turn asked the Commerce Ministry to look into it.
Nath said the study would not limit itself to the impact on small players but would cover consumers, suppliers and dislocation.
"It would deal with the issue of big versus small and not just FDI," Nath said.
Interestingly, in an earlier study the think-tank had favoured FDI in retail.
Nath said, while the review of FDI in specific sectors was an ongoing process, the ministry's proposal to open foreign investment in electronics and sports goods among others could slightly be delayed till the report is received.