The rupee rises to 51.96/97 from its close of 52.155/165 on Wednesday, after earlier rising to a 5-1/2 month high of 51.86.
Dealers cite inflows from Indian Railway Finance Corp's recent $300 million bond sale, while also citing inflows from a large engineering company.
Exporter selling has also kicked in from 52.04 levels, they add.
The rupee may see more gains as government looks set to push to open up the pension sector for foreign investors and raise FDI limits in insurance.