MUMBAI: Tata Sons, holding company of the $150-billion Tata Group, will have to be ready for a stock market listing by September 2025 with the RBI classifying it as an ‘upper-layer’ NBFC, which requires greater regulatory compliance.If Tata Sons gets listed, it will be a windfall for its shareholders, including Tata Trusts. At an estimated valuation of Rs 11 lakh crore for Tata Sons, a 5% offering...