Costco: On the Cusp of Greatness?

Costco Wholesale ( COST ) has risen 9% during the past 12 months of trading, less than half the S&P 500's 21% gain during the same period. But that underperformance didn't stop Barron's Teresa Rivas from urging investors to " put Costco in your shopping cart " in December, or Oppenheimer from calling Costco one of the most intriguing names in large-cap retail last week. Now Goldman Sachs analyst Matthew Fassler and team have added Costco to the firm's Conviction List, while reiterating their Buy rating. They explain why: