Mumbai: Shapoorji Pallonji (SP) Group would use a part of its 18.37% Tata Sons equity to launch a ₹25,500-crore bond issue Monday, multiple people familiar with the high-yield fundraising told ET.Its terms require that within 18 months of the issue, either Tata Sons announces an initial public offering (IPO), or SP Group reaches a settlement with the Tata holding company on its ownership.

The bond's terms themselves acknowledge that monetisation of the Tata Sons stake is central to repayment, said a banking industry official.

Central bank clarifications on indirect public funds and asset-based classification of NBFCs increase the likelihood of a Tata Sons listing, which, while not guaranteed, provides incremental comfort on SP Group's ability to monetise its biggest asset over time.

Last Wednesday, the central bank implemented a new definition for systemically important non-banking financial companies, called upper-layer NBFCs, bringing such entities with assets exceeding ₹1 lakh crore under the umbrella that requires mandatory public listing of shares.

The move appears to have all but shut the door for the parent of the country's largest business group to remain privately held.Tata Sons, with an asset base of more than ₹1.75 lakh crore, was classified as an NBFC-UL on the asset-based framework that replaced a complex metric.