United Kingdom antitrust authorities have initiated an investigation into Boeing’s proposed acquisition of Spirit AeroSystems, a fuselage manufacturer.

The Competition and Markets Authority began an initial review last week to evaluate potential impacts on U.K. competition.

The probe has now advanced to the first phase of a formal investigation, with a decision expected by August 28 on whether to proceed with a deeper inquiry.

In July 2024, Boeing agreed to acquire Spirit’s Boeing-related commercial operations, along with its commercial, defense, and aftermarket businesses, for approximately $4.7 billion.

Boeing’s leadership stated that the acquisition would enhance the safety and quality of its manufacturing processes.

Neither Boeing nor Spirit immediately responded to requests for comment.