India, Feb. 10 -- "They call me the Insider-not for playing their game, but because I've stood just close enough to see how it's really played. These days, I'm a recluse prowling the treacherous maze of stocks, cryptic regulatory rulings, and corporate betrayals, where fortunes shift in the flicker of a deal. Between what gets published and what gets buried, I chase the stories that pulse through the veins of India's financial empire-some lived, many hushed, most inconvenient. "And nowhere is that maze darker-or more lucrative-than India's derivatives bazaar."

In the shadows, parallel markets learn to breathe, tax the visible trade hard enough, and the invisible one grows teeth.

On Sunday afternoon in New Delhi, as Finance Minister Nir...