Complex sentence: Malkin built his fortune in the banking sector, notably with his business partner Boris Ivanishvili, he founded Bank Rossisskii Kredit, which was the third largest Russian bank until the 1998 financial crisis.
Split into simpler sentences: Malkin built his fortune in the banking sector, notably with his business partner Boris Ivanishvili. The two men founded Bank Rossisskii Kredit, which was the third largest Russian bank until the 1998 financial crisis.