This is the 15237th most frequent Turkish word.
sponsoru
"Sponsoru" means "its/her/his/their sponsor" in English.
In this sentence, 'sponsoru' refers to 'the sponsor' and indicates the entity that is supporting or financing the event.
Etkinliğin sponsoru çok büyük bir şirkettir.
The sponsor of the event is a very large company.
Here, 'sponsoru' is used to inquire about the entity providing sponsorship for the race.
Bu yarışın sponsoru kimdir?
Who is the sponsor of this race?
In this case, 'sponsoru' denotes the company taking on the role of sponsorship for the conference this particular year.