Peter Kraus, the Wall Street veteran who recently led AllianceBernstein Holding LP, is starting a mutual fund company -- and aiming to shake up the industry’s traditional fee model. Italian insurer Assicurazioni Generali SpA is backing Kraus’s firm and will contribute as much as $4 billion to Aperture Investors, according to a statement Thursday. The firm will pay money managers based on fund performance rather than the volume of assets. Customers will be charged low ETF-like fees until their fund outperforms its benchmark.