A collar option strategy involves buying 100 shares of stock while simultaneously selling a call option and buying a put option on the same stock. This limits the risk of losses on the stock but also limits upside potential if the stock rises significantly. The document recommends a call spread strategy instead of a collar since it requires less capital tied up in the underlying stock and allows for more flexibility. Collars make more sense if one is already obligated to hold the stock and wants to hedge downside risk.