Twenty observations per asset. Enough to prove NVDA is about five times SPY. Not enough to sell a live book.
NVDA median
1.14%
NVDA 90th
5.56%
SPY median
0.44%
SPY 90th
1.09%
Premiums use a 252-session series bootstrapped from one measured month. Not a live price. Recompute on 12 months of history before selling a real contract.
Price NVDA cover