$COST I've admired Costco for more than two decades, yet somehow I never became an investor. The market gave me an opportunity to change that with the stock retreating off its February all-time highs despite the warehouse club leader's model proving resilient during the pandemic. Costco's comps declined 4.7% for the retail month of April -- including a 3.3% slide in the U.S. -- but there's more to that metric than meets the eye. Costco sells gasoline at most of its stores, and naturally between folks driving less last month and gas prices plunging, this was going to be a drag on performance. Back out the gas pump sales and U.S. comps would be flat. Things get even better once we do some more weeding out. It had limited service at its food courts and in its travel business. Most of its optical, hearing aid, and photofinishing departments were closed in April. Back out all of those segments and worldwide comps rose 8.6%, spearheaded by an 11.2% spike on its home turf.