US plane manufacturer Boeing looks set to take over part of Spirit's Belfast operation as no other buyer has yet been found. The development was first reported by the Financial Times which suggested talks to find a potential other buyer had not progressed.

Boeing Co. is preparing to split control of a factory complex in Belfast, Ireland with arch-rival Airbus SE as Spirit AeroSystems Holdings Inc. struggles to line up a third-party buyer for some of the assets.

Britain's competition regulator said on Monday it has begun a Phase 1 investigation into planemaker Boeing's deal to acquire Spirit Aerosystems and set a deadline of August 28 for a decision. The Competition and Markets Authority (CMA) had said last week that it was weighing a probe into whether the deal could affect competition in the country or in other markets.