The Shapoorji Pallonji Group’s talks with the Tata Group over its 18.4% stake in Tata Sons are focused on a structure that could allow it to raise funds in multiple tranches, enabling the construction conglomerate to retire a portion of its high-cost debt in the near term, according to a source familiar with the discussions. Valuation exercises involving Tata Sons’ unlisted businesses are underway as part of efforts to arrive at a value for the holding company. Any transaction involving the SP Group’s stake is likely to be structured in tranches aligned with its debt repayment requirements, with the first tranche potentially raising as much as Rs 25,000 crore, the source said, requesting anonymity.