The real wordsTheory
Two segments, one mature and one not
Primary mortgage marketHousing loans issued directly to customers by banks, HFCs and NBFCs. The professor's word for it: mature.
Secondary mortgage marketPackaged loans sold to investors through the securitisation process, for example mortgage-backed securities. His word for it: under-developed.
That asymmetry is the whole Indian story. India originates housing loans well and distributes them badly, so the risk stays on bank and HFC balance sheets.