Nandish Shah of HDFC Securities suggests a 'bull spread' derivative strategy for Larsen & Toubro (LT) stock, targeting the January monthly expiry. The strategy involves buying the 4,200 Call option and selling the 4,300 Call option, aiming for a maximum profit of ₹12,600 if LT closes at or above ₹4,300 by expiry. This recommendation is based on observed short covering, an all-time high stock price, and positive momentum indicators.