In 1992, the Harshad Mehta scam led to profound changes in capital market regulation and infrastructure. One of these was setting up the NSE as a cleaner alternative to the century-old, scam- and faction-ridden BSE. In a supreme irony, NSE itself got embroiled in the algo scam originating in the Exchange’s sanctum the co-location servers for high frequency trading. Here is the whole story of NSE’s commercial success leading to arrogance and fall from grace, even as it continues to remain a highly profitable near-monopoly.