In my case, only flights which were booked using my employer's corporate ticket designator (signifying the discounted fare was purchased) are flagged as "Business Trip". The ticket designator is the modifier of the fare basis in the fare construction. Made up example: KA0NA0MA/XX123 - in this example, KA0NA0MA is the fare basis and XX123 is the ticket designator. Each individual corporate booking agreement has its own ticket designator associated with that agreement. DL must have implemented a simple lookup to provide the company's name for use in DL's corporate travel recognition program.
https://www.delta.com/content/www/en...anagement.html
https://pro.delta.com/content/agency...-recognit.html