Costco will charge shoppers in Canada and the US an extra $5 or $10 for an annual membership starting June, the firm has announced. The membership fee is a huge part of Costco’s revenue. It amounts to $2.6 billion US globally, more than the Costco made in profits last year. The increase will put a regular “gold star” membership at $60 in national currency in the U.S. and Canada. An executive membership, which comes with discounts and benefits, will be bumped up $10 to $120 a year. The last increase was in 2011. Costco had almost 87 million members at the end of its last fiscal year, including about 10 million in Canada.