According to a GMR filing to BSE, Rao bought 9,17,500 shares of GMR through open market transactions yesterday and post this, his personal holding in the company has increased to 0.0316 per cent.
Rao, who is also one of the promoters of the company, used to hold 0.0081 per cent stake in GMR before the transaction.
At the end of September, 16 promoter entities including G M Rao, controlled 71.62 per cent stake in the company.
GMR has been in the news recently as Maldives government on Tuesday had cancelled company's contract to operate and modernise Male international airport.
The company had said it was exploring legal options against the Maldivian government's move.
Meanwhile, in an another filing, the company said that one of its promoter group firm, GMR Holdings Pvt Ltd has pledged 25,00,000 shares in favour of STCI Finance Ltd.
The company has also started collecting toll at two out of three toll plazas of Hungund - Hospet section of NH-13, which it is developing through a subsidiary as the some parts of the project has been completed ahead of schedule, it said in an update given to the BSE.
Shares of the company today rose by 4.48 per cent o close at Rs 18.65 apiece on the BSE.