Costco, the US retail group, and the copper miner Grupo Mexico have been named the worst laggards on human rights standards in a new ranking from Aviva Investors of firms on their respect for humanitarian ideals.

The 2017 Corporate Human Rights Benchmark assessed 98 publicly-traded companies in the "high-risk" agricultural products, apparel and extractives industries. Aviva is one of the leaders of the project, and says it has support from investors with $5.3 trillion under management.