Once the qualifying relationship legally exists and can be documented, and once the transferee's continuous qualifying year abroad is complete and falls within the preceding three years. Processing time then depends on the filing route and whether premium processing is used.
Closing the deal is one date; being able to file is another
Hypothetical example: the acquisition closes in October and the company wants the director in place for January. Work through the sequence rather than the wish. The share transfer must be complete and recorded, the holding structure executed, and both companies actively doing business.
The director's qualifying year must be intact and documented, which means checking whether any leave or secondment interrupted it. Only then does the filing clock start, and its length depends on the responsible agency's current processing times, with premium processing available at additional cost. If the American operation has been open less than a year it is treated as a new office, with an initial one-year approval and a further examination at extension.
Set the integration schedule around the later date and keep the Coalhurst coverage plan in place longer than expected.