New Delhi, Sept. 27 -- After NHPC Ltd dropped plans to buy out its co-promoters' stake in controversy-hit PTC India Ltd, thermal power giant NTPC Ltd pitched a similar proposal but has run into an obstacle.

NHPC, India's largest hydropower generator, is unwilling to sell its stake in the power trading joint venture although it had, while shelving its buyout plan, said power trading was not its core business.

Apart from NTPC and NHPC, PTC's other promoters are Power Grid Corp. of India Ltd and Power Finance Corp. Ltd. The four state-owned companies hold 4.05% each in PTC.

"In the past two months NTPC has offered to buyout the shares of the other promoter PSUs," said an executive familiar with the developments.

Another executive said th...