SoftBank Group’s move to acquire US-based chip designer Ampere Computing faces uncertainty as the US Federal Trade Commission opened a formal probe known as a second request for information, a process Bloomberg reported could take a year or more and lead to legal action.

The news agency noted only a small percentage of proposed acquisitions face such an investigation, which can prompt lawsuits to block buyouts.

SoftBank’s deal also requires clearance by the Committee on Foreign Investment in the US.

The Japanese company reached a deal to acquire Ampere Computing for $6.5 billion in March.

At the time, it said the deal aligns with its broader strategic vision, and commitment to driving innovation in AI and computing.

Ampere makes high-performance, energy-efficient AI compute based on the Arm platform.

SoftBank holds a majority stake in UK-based chip design company Arm.