1. Costco's Q1 net sales reached nearly $66 billion, up 8.2% year-over-year. 2. Comparable sales in the US grew by 5.9%, driven by traffic and ticket size increases. 3. Memberships increased by over 5%, totaling nearly 146 million cardholders. 4. The holiday season was record-setting, with significant sales in the food court. 5. Costco filed a lawsuit to recover tariffs paid under a previous executive order.