Convexity, Options Trading, Volatility Trading, Moontower, Option Greeks.
change in delta (and Greekophiles will recognize the acceleration as gamma). If you want the opportunity to test your understanding go back to the call overwriter example: You own 3,000 shares of stock = long 3,000 deltas. You are short 30 20% delta calls (equivalent of 600 shares) = short 600