What It Means
Exposure Margin is an extra margin layer NSE Clearing charges on top of SPAN Margin, meant to cover sharp, sudden moves that SPAN's scenario-based model might not fully capture.
How It Works
For index futures and index options selling, Exposure Margin is typically 2% of the contract value (spot price × lot size). For stock futures and stock options selling, it's the higher of 3.5% of contract value or 1.5 standard deviations of the underlying stock's logarithmic returns over the past 6 months — a way of charging more exposure margin on stocks that have been genuinely more volatile recently.
Example
A stock future with a contract value of ₹10,00,000 would carry roughly ₹35,000 in Exposure Margin at the 3.5% rate, on top of whatever SPAN Margin the position requires.