An investor group representing total combined assets of $3 trillion has written to 54 multinational brands and businesses with operations in the six Gulf states, with requests for details on how they are safeguarding migrant workers.

The group, led by UK charity fund manager CCLA and supported by investors including Aviva, Schroders and M&G, are raising the concerns in response to recent reports of the unethical and exploitative recruitment practices many migrant workers to the region are subjected to, including the payment of extortionate recruitment fees only made possible through taking loans, and the retention of workers’ passports by their employers and recruiters.

The group does not allege any wrongdoing on behalf of the companies, but has asked companies what policies and processes they have in place to identify, mitigate and remedy abuses against migrant workers if they do occur. The 54 companies approached on their operations in the UAE include hospitality, construction, and oil and gas – sectors deemed high-risk for worker welfare due to their multiple layers of business operations and recruitment.

Petroleum giant Shell, construction firms Acciona and Vinci, and Hyatt and Wyndham Hotels told Reuters that they have human rights commitments and have policies in place to safeguard workers.