Auditor working for bank

As Salaam Wa Alaikum Moulana,

I am in the Accounting Profession. I would like to know the below circumstances,

Bank is giving loan to the company against security of Stock available. Bank appointing Independent Auditor for certifying the stock and other assets of the company. For this, Bank is paying a fee to the Auditor. Whether this income is Halal or Haram for the Auditor?

Jazakallah o Khair!