The union, which represents more than 18,000 workers at Costco, said 85% of its members voted to authorise a strikeCostco logo can be seen in this picture. Teamsters said on Sunday its members at US retailer Costco Wholesale voted in favour of a nationwide strike, as they entered a final round of talks to reach a new contract ahead of a Jan 31 deadline. The union, which represents more than 18,000 workers at Costco, said 85% of its members voted to authorise a strike. The final week of negotiations begins on Jan 20, the union said in another X post. The final week of negotiations begins on Jan 20, the union said in another X post.