Will more membership-fee revenue be a catalyst for the stock? Costco (COST 0.83%) recently reported strong fiscal third-quarter results and talked about a potential membership-fee increase down the road. The stock has been a strong performer, up over 60% in the past year. Let's take a closer look at the retailer's most recent earnings, the potential impact of a membership-fee increase, and whether now is a good time to buy the stock. Rising sales and potential membership-fee increases Costco's stellar fisca ...