Deutsche Bank and other investors are offering rupee-denominated bonds of a Shapoorji ​Pallonji Group firm at a premium, encouraged by ​the group's plans to sell part of its stake in Tata ‌Sons, three merchant bankers said on Monday.

Tata Trusts, the controlling shareholder in Tata Sons, last week said SP Group proposed to sell part of its stake worth 250 billion rupees ($2.61 billion). That would give much-needed funds to the debt-laden infrastructure and construction conglomerate, the second-largest shareholder in Tata Sons.

SP Group entity Eqyizen Investment had raised 213.50 billion rupees through three-year zero-coupon bonds at a yield of 18.95% in July. The bonds are now being ‌offered at a yield of around 18.70%-18.75%, the bankers said, requesting anonymity as they are not authorised to speak to the media.

Eqyizen's bonds are secured by SP Group's stake in Tata Sons, held through Cyrus Investments.

SP Group and Deutsche Bank, which structured the bond sale and was also a large investor in the issue, did not ​respond to Reuters requests for comment.

"Deutsche Bank has the bonds on its books and ‌is actively seeking buyers to exit at some profit," one of the bankers said. "We have not seen major trades (yet)."

The 160-year-old ​SP ‌Group has more than 500 billion rupees of high-interest debt outstanding and due ‌for redemption in the next few years.

Another one of its entities, Porteast Investment, has outstanding zero-coupon bonds worth 286 billion rupees.

SP Group ‌is ​also planning to ​seek an extension to a payment worth around 35 billion rupees, which is due on September 30, towards an obligation ‌of Porteast, the bankers ​added.

($1 = 95.8150 Indian rupees)