New Delhi, Sept. 16 -- In late May, Walmart seemed like an opportune buy.

At around $134, the stock appeared poised to prosper if rising prices sparked by the Iran war prompted people to economize. We suggested selling a put option and buying a call option to buy Walmart lower or participate in gains triggered by a pending earnings report. (Calls give holders the right to buy shares of an underlying asset at a specific price and time, while puts give holders the right to sell shares under similar conditions.)

Instead, the stock tanked when Walmart reported that its operating margins were pressured by fuel costs and declining consumer spending. Management lowered earnings guidance. Our put and call recommendations, which expired in Augus...