The union-aligned SOC Investment Group formally questioned Walmart regarding the financial and supply chain impacts of President Donald Trump’s immigration policies.

The shareholder group, which holds less than 1% of Walmart, also sent letters to Amazon and Alphabet. SOC specifically seeks details on how the companies are navigating the administration’s new visa fee structures.

The inquiry highlights potential risks for the retail giant, which relies on a diverse workforce and complex global supply chains.

SOC Investment Group historically engages companies on social and governance issues, including racial equity audits. No market reaction to the inquiry has been reported at this time.