Mainboard IPOs are issues listed on the main NSE or BSE platform — distinct from the SME platforms (NSE Emerge and BSE SME). SEBI sets entry criteria for mainboard listings: minimum net tangible assets of ₹3 crore in each of the preceding three years, operating profit history, and net worth of at least ₹1 crore in each of the last three years.
Mainboard IPOs typically range from ₹100 crore to ₹20,000+ crore in issue size. They follow the standard book-building process with QIB / NII / Retail reservations of approximately 50% / 15% / 35%. Lead managers are usually established merchant bankers, the registrar is one of the major firms (Link Intime, KFin, Bigshare, Cameo), and listing happens on T+6 day from issue close.
Mainboard issues have wider analyst coverage, deeper after-market liquidity, and broader retail participation than SME issues. They are the default category for any meaningfully sized issue from a profitable, audited company. Most of the IPOs covered in financial media — Tata Capital, Hyundai Motor India, NSDL, LIC — are mainboard issues.