This is the 4549th most frequent Turkish word.
bankasının
"Bankasının" means "of his/her/its bank" in English.
In this sentence, 'bankasının' is not directly used, but 'bankanın' is, denoting banking-related ownership.
O kasabada yalnızca bir bankanın şubesi vardı.
There was only one branch of the bank in that town.
Here, 'bankasının' is used to show possession or association, indicating that the donation came from the bank.
Bu köydeki okulun bilgisayarları ilçe bankasının bağışı ile sağlanmıştır.
The computers in the village's school were provided through the donation of the district's bank.
In this sentence, 'bankasının' indicates possession, meaning the interest rates offered by "the neighborhood's bank".